diff --git a/backend/app/controllers/counts_tables_controller.rb b/backend/app/controllers/counts_tables_controller.rb
index a93aaa7..f3620c3 100644
--- a/backend/app/controllers/counts_tables_controller.rb
+++ b/backend/app/controllers/counts_tables_controller.rb
@@ -3,6 +3,8 @@ class CountsTablesController < ApplicationController
     resolve_locale!
     definition = CountsResourceDefinition.new(params[:resource])
     render json: { fields: definition.metadata,
+                   output_fields: definition.output_fields,
+                   filter_fields: definition.filter_metadata,
                    axes: { latest: definition.axes(false), history: definition.axes(true) },
                    grains: CountsAxes::GRAINS, defaults: CountsDefaults.metadata(params[:resource]) }
   rescue ArgumentError
diff --git a/backend/app/models/history_access.rb b/backend/app/models/history_access.rb
index b3344af..018e3d0 100644
--- a/backend/app/models/history_access.rb
+++ b/backend/app/models/history_access.rb
@@ -148,4 +148,13 @@ class HistoryAccess < ActiveSupport::CurrentAttributes
 
   # This number deliberately ignores time, identity and content filters to prevent count probes.
   def self.population_count(model) = model.unscoped.count
+
+  # Only the resource-wide denied count is public, never a condition-dependent denied count.
+  def self.population_counts(model)
+    total, excluded = model.unscoped.optimizer_hints('MAX_EXECUTION_TIME(10000)').pick(
+        Arel.sql('COUNT(*)'),
+        Arel.sql("COALESCE(SUM(CASE WHEN #{ sql(model) } THEN 0 ELSE 1 END), 0)"))
+    { population_count: total.to_i, excluded_count: excluded.to_i,
+      excluded_count_scope: 'all_recorded_versions' }
+  end
 end
diff --git a/backend/app/services/counts_condition.rb b/backend/app/services/counts_condition.rb
new file mode 100644
index 0000000..5e4e494
--- /dev/null
+++ b/backend/app/services/counts_condition.rb
@@ -0,0 +1,330 @@
+# Typed predicates over the same recorded fields used by Counts output.
+# Multi-valued comparisons use EXISTS; inequality means no matching element.
+class CountsCondition
+  CHILD_TYPES = { 'id' => :integer, 'versionNo' => :integer, 'tagId' => :integer,
+                  'tagGroupId' => :integer, 'autoGenerated' => :boolean,
+                  'category' => :enum, 'kind' => :enum, 'sections' => :interval }.freeze
+
+  def self.fields(definition)
+    result = definition.metadata.map { _1.merge(labels: [definition.field_label(_1[:key])]) }
+    visit = lambda do |fields, prefix, labels|
+      fields.each do |field|
+        key = [prefix, field[:key]].compact.join('.')
+        path_labels = labels + [field[:label]]
+        type = if prefix
+                 CHILD_TYPES.fetch(field[:key], :string)
+               elsif key == 'is_latest'
+                 :boolean
+               elsif key == 'parents'
+                 :integer
+               elsif key == 'deprecated'
+                 :datetime
+               elsif key == 'thumbnail'
+                 :string
+               else
+                 definition.fields.fetch(key, :string)
+               end
+        type = :string if field[:children] || type == :json
+        type = :integer if ['parents', 'members'].include?(key)
+        physical = result.find { _1[:key] == key }
+        nullable = prefix.present? || (physical ? physical[:nullable] : key != 'is_latest')
+        nullable = false if field[:children]
+        entry = { key:, type:, labels: path_labels, nullable:,
+                  multiple: prefix.present? || field[:children].present?,
+                  collection: field[:children].present? || type == :interval,
+                  operators: CountsResourceDefinition::OPERATORS.fetch(type) }
+        result.reject! { _1[:key] == key }
+        result << entry
+        visit.call(field[:children] || [], key, path_labels)
+      end
+    end
+    visit.call(definition.output_fields, nil, [])
+    # The raw JSON alias has the same membership semantics as the public tag field.
+    if definition.resource == 'posts'
+      result.find { _1[:key] == 'tags_json' }.merge!(type: :string, multiple: true, collection: true,
+          operators: CountsResourceDefinition::OPERATORS.fetch(:string))
+    end
+    result + [{ key: 'user.id', type: :integer, nullable: true,
+                labels: ['history:actor', 'counts:columns.resourceId'],
+                operators: CountsResourceDefinition::OPERATORS.fetch(:integer) },
+              { key: 'user.name', type: :string, nullable: true,
+                labels: ['history:actor', 'history:name'],
+                operators: CountsResourceDefinition::OPERATORS.fetch(:string) }]
+  end
+
+  def initialize(population)
+    @population = population
+    @definition = population.definition
+    @connection = @definition.model.connection
+    @language = Locale.find_by!(code: population.params.fetch('locale', 'ja')).language_code
+  end
+
+  def apply(scope, entry)
+    raise ArgumentError unless entry.is_a?(Hash)
+    raise ArgumentError if (entry.keys - ['field', 'operator', 'value', 'end', 'blank']).any?
+
+    field = @definition.filter_metadata.find { _1[:key] == entry.fetch('field') }
+    raise ArgumentError unless field && field[:operators].include?(entry.fetch('operator'))
+    raise ArgumentError unless [true, false, nil].include?(entry['blank'])
+    values = [entry['value'], entry['end']]
+    raise ArgumentError unless values.all? { _1.nil? || (_1.is_a?(String) && _1.bytesize <= 8192) }
+    if entry['operator'] != 'range' && !values[1].nil? && values[1] != ''
+      raise ArgumentError
+    end
+
+    source, expression = source_for(field[:key])
+    type = field[:type]
+    blank = blank_sql(expression, type)
+    if entry['blank']
+      sql = if source && field[:collection]
+              "NOT EXISTS (SELECT 1 FROM #{ source })"
+            elsif source
+              "NOT EXISTS (SELECT 1 FROM #{ source } WHERE NOT (#{ blank }))"
+            else blank
+            end
+      return scope.where(Arel.sql(sql))
+    end
+    return scope if values.all? { _1.nil? || _1 == '' }
+
+    parsed = values.map { parse(_1, type) }
+    validate_enum!(field[:key], parsed.first) if type == :enum
+    operator = entry['operator']
+    if type == :interval
+      return interval(scope, source, expression, parsed)
+    end
+    clauses = []
+    binds = []
+    if operator == 'range'
+      ['>=', '<='].each_with_index do |comparison, index|
+        next if parsed[index].nil?
+
+        clauses << "#{ expression } #{ comparison } ?"
+        binds << parsed[index]
+      end
+      raise ArgumentError if parsed.all? && parsed.first > parsed.last
+    elsif !parsed.first.nil?
+      comparison = { 'eq' => '=', 'ne' => '=', 'gt' => '>', 'lt' => '<',
+                     'ge' => '>=', 'le' => '<=', 'like' => 'LIKE' }.fetch(operator)
+      clauses << "#{ expression } #{ comparison } ?"
+      binds << parsed.first
+    end
+    return scope if clauses.empty?
+
+    predicate = clauses.join(' AND ')
+    if source
+      predicate = "EXISTS (SELECT 1 FROM #{ source } WHERE #{ predicate })"
+      predicate = "NOT (#{ predicate })" if operator == 'ne'
+    elsif operator == 'ne'
+      predicate = "(NOT (#{ predicate }) OR #{ blank })"
+    end
+    scope.where(predicate, *binds)
+  end
+
+  private
+
+  def parse(value, type)
+    return nil if value.nil? || value == ''
+
+    case type
+    when :integer, :interval
+      raise ArgumentError unless value.match?(/\A-?[0-9]{1,19}\z/)
+
+      number = Integer(value, 10)
+      raise ArgumentError unless number.between?(-9_223_372_036_854_775_808, 9_223_372_036_854_775_807)
+
+      number
+    when :boolean
+      raise ArgumentError unless ['true', 'false'].include?(value)
+
+      value == 'true' ? 1 : 0
+    when :datetime then @population.timestamp(value)
+    else value
+    end
+  end
+
+  def validate_enum!(key, value)
+    allowed = case key.split('.').last
+              when 'event_type' then VersionRecord::DEFAULT_EVENT_TYPE_MAP.values
+              when 'category', 'tag_category' then TagVersion.categories.keys
+              when 'kind' then ['internal', 'external']
+              when 'source_kind' then Material::SOURCE_KINDS
+              end
+    raise ArgumentError if value && allowed && !allowed.include?(value)
+  end
+
+  def blank_sql(expression, type)
+    if [:string, :enum].include?(type)
+      "(#{ expression } IS NULL OR #{ expression } = '')"
+    else
+      "#{ expression } IS NULL"
+    end
+  end
+
+  def scalar(document, key, type = :string)
+    path = @connection.quote("$.#{ key }")
+    value = "JSON_EXTRACT(#{ document }, #{ path })"
+    text = "JSON_UNQUOTE(NULLIF(#{ value }, CAST('null' AS JSON)))"
+    return "CAST(#{ text } AS SIGNED)" if type == :integer
+    return "CASE #{ text } WHEN 'true' THEN 1 WHEN 'false' THEN 0 END" if type == :boolean
+
+    text
+  end
+
+  def json_table(document, path, name)
+    "JSON_TABLE(COALESCE(#{ document }, JSON_ARRAY()), #{ @connection.quote(path) } " +
+        "COLUMNS (item JSON PATH '$')) #{ name }"
+  end
+
+  def names_source(document, alias_name)
+    source = "JSON_TABLE(COALESCE(JSON_KEYS(#{ document }), JSON_ARRAY()), '$[*]' " +
+        "COLUMNS (language_code TEXT PATH '$')) #{ alias_name }"
+    path = "CONCAT('$.', JSON_QUOTE(#{ alias_name }.language_code))"
+    [source, "JSON_EXTRACT(#{ document }, #{ path })", "#{ alias_name }.language_code"]
+  end
+
+  def point
+    @point ||= @population.history ? @population.at :
+        @population.timestamp(@population.params['at']) || @population.at
+  end
+
+  def name_expression(row)
+    language_path = @connection.quote("$.#{ @language.to_json }.name")
+    name = "JSON_UNQUOTE(JSON_EXTRACT(#{ row }.names, #{ language_path }))"
+    "COALESCE(#{ name }, #{ row }.name)"
+  end
+
+  def parent_source
+    column = @definition.resource == 'posts' ? 'parent_post_ids' : 'parent_tag_ids'
+    ids = "TRIM(REGEXP_REPLACE(COALESCE(v.#{ column }, ''), '[[:space:]]+', ' '))"
+    document = "CONCAT('[', REPLACE(#{ ids }, ' ', ','), ']')"
+    source = json_table(document, '$[*]', 'parent_entry')
+    id = 'CAST(parent_entry.item AS UNSIGNED)'
+    return [source, id] if @definition.resource == 'posts'
+
+    bound = @connection.quote(point)
+    source += ' LEFT JOIN tag_versions parent_version ON parent_version.tag_id = ' + id +
+        " AND parent_version.created_at <= #{ bound } AND " +
+        HistoryAccess.sql(TagVersion, 'parent_version') +
+        ' AND NOT EXISTS (SELECT 1 FROM tag_versions newer_parent ' +
+        'WHERE newer_parent.tag_id = parent_version.tag_id ' +
+        "AND newer_parent.created_at <= #{ bound } " +
+        'AND newer_parent.version_no > parent_version.version_no)'
+    [source, id]
+  end
+
+  def post_tag_source
+    source = json_table('v.tags_json', '$[*]', 'tag_snapshot')
+    source += ' LEFT JOIN tag_versions referenced_tag ON referenced_tag.tag_id = ' +
+        scalar('tag_snapshot.item', 'tag_id', :integer) +
+        ' AND referenced_tag.version_no = ' + scalar('tag_snapshot.item', 'version_no', :integer) +
+        " AND referenced_tag.created_at <= #{ @connection.quote(point) } AND " +
+        HistoryAccess.sql(TagVersion, 'referenced_tag')
+    source
+  end
+
+  def language_field(source, document, parts, inherited_language = nil)
+    return [source, scalar(document, 'name')] if parts.empty?
+    return [source, inherited_language] if parts == ['languageCode'] && inherited_language
+
+    if parts.first == 'aliases'
+      aliases = "JSON_EXTRACT(#{ document }, '$.aliases')"
+      source += ' JOIN ' + json_table(aliases, '$[*]', 'alias_entry')
+      child = parts[1] || 'name'
+      return [source, inherited_language] if child == 'languageCode' && inherited_language
+      columns = { 'scriptCode' => 'script_code', 'name' => 'name' }
+      key = columns.fetch(child) { raise ArgumentError }
+      return [source, scalar('alias_entry.item', key)]
+    end
+    key = { 'name' => 'name', 'scriptCode' => 'script_code',
+            'autoGenerated' => 'auto_generated' }.fetch(parts.first) { raise ArgumentError }
+    [source, scalar(document, key, CHILD_TYPES.fetch(parts.first, :string))]
+  end
+
+  def source_for(key)
+    root, *parts = key.split('.')
+    return [nil, "(#{ @population.latest_sql })"] if root == 'is_latest'
+    if root == 'user' && parts.any?
+      expression = parts.first == 'id' ? 'v.created_by_user_id' :
+          '(SELECT actor.name FROM users actor WHERE actor.id = v.created_by_user_id)'
+      return [nil, expression]
+    end
+    return [nil, 'v.thumbnail_base'] if root == 'thumbnail'
+    return [nil, 'v.deprecated_at'] if root == 'deprecated'
+    if root == 'parents'
+      source, id = parent_source
+      return [source, parts.first == 'name' ? name_expression('parent_version') : id]
+    end
+    if root == 'tags' || root == 'tags_json'
+      return post_field(parts)
+    end
+    if root == 'names' || root == 'aliases'
+      source, document, language = names_source('v.names', 'name_language')
+      parts = ['aliases', *parts] if root == 'aliases'
+      return language_field(source, document, parts, language)
+    end
+    if root == 'members' || root == 'placements'
+      path = '$[*]' + parts.take_while { _1 == 'children' }.map { '.children[*]' }.join
+      source = json_table("v.#{ root }", path, 'structure_entry')
+      if root == 'members' && parts.empty?
+        value = "COALESCE(#{ scalar('structure_entry.item', 'tag_id', :integer) }, " +
+            "#{ scalar('structure_entry.item', 'tag_group_id', :integer) })"
+        return [source, value]
+      end
+      leaf = parts.last || 'sectionName'
+      leaf = 'sectionName' if leaf == 'children'
+      column = leaf.gsub(/[A-Z]/) { "_#{ _1.downcase }" }
+      return [source, scalar('structure_entry.item', column, CHILD_TYPES.fetch(leaf, :string))]
+    end
+    if root == 'export_paths_json'
+      source, value, profile = names_source('v.export_paths_json', 'export_profile')
+      return [source, parts.first == 'profile' ? profile : "JSON_UNQUOTE(#{ value })"]
+    end
+    return [nil, name_expression('v')] if root == 'name' && @definition.resource == 'tags'
+
+    [nil, @definition.expression(root)]
+  end
+
+  def post_field(parts)
+    source = post_tag_source
+    document = 'tag_snapshot.item'
+    case parts.first
+    when 'names'
+      names, entry, language = names_source('referenced_tag.names', 'tag_language')
+      language_field("#{ source } JOIN #{ names }", entry, parts.drop(1), language)
+    when 'sections'
+      sections = "JSON_EXTRACT(#{ document }, '$.sections')"
+      source += ' JOIN ' + json_table(sections, '$[*]', 'section_entry')
+      [source, 'section_entry.item']
+    when 'id'
+      [source, "COALESCE(#{ scalar(document, 'tag_id', :integer) }, " +
+          "#{ scalar(document, 'external_tag_id', :integer) })"]
+    when 'versionNo' then [source, scalar(document, 'version_no', :integer)]
+    when 'kind'
+      [source, "CASE WHEN #{ scalar(document, 'tag_id') } IS NULL " +
+          "THEN 'external' ELSE 'internal' END"]
+    when 'category'
+      [source, "COALESCE(#{ scalar(document, 'category') }, referenced_tag.category)"]
+    else
+      [source, "COALESCE(#{ scalar(document, 'name') }, referenced_tag.name)"]
+    end
+  end
+
+  def interval(scope, source, document, bounds)
+    raise ArgumentError if bounds.compact.any?(&:negative?)
+    raise ArgumentError if bounds.all? && bounds.first > bounds.last
+
+    first = scalar(document, 'begin_ms', :integer)
+    last = scalar(document, 'end_ms', :integer)
+    clauses = []
+    values = []
+    if bounds.first
+      clauses << "(#{ last } IS NULL OR #{ last } > ?)"
+      values << bounds.first
+    end
+    if bounds.last
+      clauses << "#{ first } < ?"
+      values << bounds.last
+    end
+    scope.where("EXISTS (SELECT 1 FROM #{ source } WHERE #{ clauses.join(' AND ') })", *values)
+  end
+end
diff --git a/backend/app/services/counts_defaults.rb b/backend/app/services/counts_defaults.rb
index b448695..d223cbf 100644
--- a/backend/app/services/counts_defaults.rb
+++ b/backend/app/services/counts_defaults.rb
@@ -11,22 +11,32 @@ class CountsDefaults
         'sort' => 'a0:desc', 'conditions' => '' } }]
     result << { definition: 'latest', mode: 'summary', params: {
         'rows' => '', 'cols' => '', 'conditions' => '', 'tags' => '' } }
-    if resource == 'posts'
-      result += [{ definition: 'latest', mode: 'details', params: {
-              'columns' => POST_COLUMNS.join(' '), 'order' => POST_COLUMNS.join(' '),
-              'children' => 'tags.name parents.id', 'nested_json' => '0',
-              'conditions' => '', 'tags' => '' } }]
-    end
-    if resource == 'tags'
-      columns = ['resource_id', 'version_no', 'is_latest', 'name', 'category',
-                 'aliases', 'parents', 'deprecated', 'event_type', 'user', 'created_at']
-      result << { definition: 'latest', mode: 'details', params: {
-          'columns' => columns.join(' '), 'order' => columns.join(' '),
-          'children' => 'aliases.name parents.name', 'nested_json' => '0' } }
+    details = detail_params(resource)
+    if details
+      ['latest', 'history'].each do |definition|
+        result << { definition:, mode: 'details', params: details }
+      end
     end
     result
   end
 
+  def self.detail_params(resource)
+    if resource == 'posts'
+      return { 'columns' => POST_COLUMNS.join(' '), 'order' => POST_COLUMNS.join(' '),
+               'children' => 'tags.name parents.id', 'nested_json' => '0',
+               'conditions' => '', 'tags' => '' }
+    end
+    unless resource == 'tags'
+      return { 'columns' => CountsExportProjection.default_columns(resource).join(' '),
+               'children' => CountsExportProjection.default_children(resource).join(' ') }
+    end
+
+    columns = ['resource_id', 'version_no', 'is_latest', 'name', 'category',
+               'aliases', 'parents', 'deprecated', 'event_type', 'user', 'created_at']
+    { 'columns' => columns.join(' '), 'order' => columns.join(' '),
+      'children' => 'aliases.name parents.name', 'nested_json' => '0' }
+  end
+
   def self.for(params)
     settings = entries(params.fetch('resource', 'posts')).find do |entry|
       entry[:definition] == params.fetch('definition', 'latest') &&
diff --git a/backend/app/services/counts_population.rb b/backend/app/services/counts_population.rb
index 19446cb..c38be27 100644
--- a/backend/app/services/counts_population.rb
+++ b/backend/app/services/counts_population.rb
@@ -125,50 +125,8 @@ class CountsPopulation
   end
 
   def apply_condition(entry)
-    raise ArgumentError unless entry.is_a?(Hash)
-    raise ArgumentError if (entry.keys - ['field', 'operator', 'value', 'end', 'blank']).any?
-
-    key = entry.fetch('field')
-    type = definition.fields.fetch(key) { raise ArgumentError }
-    operator = entry.fetch('operator')
-    raise ArgumentError unless CountsResourceDefinition::OPERATORS.fetch(type, []).include?(operator)
-    raise ArgumentError unless [true, false, nil].include?(entry['blank'])
-
-    expression = definition.expression(key)
-    blank = type == :string || type == :enum ?
-        "(#{ expression } IS NULL OR #{ expression } = '')" : "#{ expression } IS NULL"
-    if entry['blank']
-      @scope = @scope.where(Arel.sql(blank))
-      return
-    end
-    values = [entry['value'], entry['end']]
-    raise ArgumentError unless values.all? { _1.nil? || _1.is_a?(String) }
-    return if values.all? { _1.nil? || _1 == '' }
-
-    parsed = values.map do |value|
-      next nil if value.nil? || value == ''
-
-      case type
-      when :integer
-        raise ArgumentError unless value.match?(/\A-?\d+\z/)
-
-        value.to_i
-      when :datetime then timestamp(value)
-      else value
-      end
-    end
-    if operator == 'range'
-      @scope = @scope.where("#{ expression } >= ?", parsed[0]) if parsed[0]
-      @scope = @scope.where("#{ expression } <= ?", parsed[1]) if parsed[1]
-      return
-    end
-    return unless parsed[0]
-
-    sql_operator = { 'eq' => '=', 'ne' => '<>', 'gt' => '>', 'lt' => '<',
-                     'ge' => '>=', 'le' => '<=', 'like' => 'LIKE' }.fetch(operator)
-    sql = "#{ expression } #{ sql_operator } ?"
-    sql = "(#{ sql } OR #{ blank })" if operator == 'ne'
-    @scope = @scope.where(sql, parsed[0])
+    @condition ||= CountsCondition.new(self)
+    @scope = @condition.apply(@scope, entry)
   end
 
   def snapshot_membership(value)
diff --git a/backend/app/services/counts_resource_definition.rb b/backend/app/services/counts_resource_definition.rb
index cfebcea..bb909cd 100644
--- a/backend/app/services/counts_resource_definition.rb
+++ b/backend/app/services/counts_resource_definition.rb
@@ -31,7 +31,35 @@ class CountsResourceDefinition
   OPERATORS = {
       string: ['eq', 'ne', 'like'], enum: ['eq', 'ne'], boolean: ['eq', 'ne'],
       integer: ['eq', 'ne', 'gt', 'lt', 'ge', 'le', 'range'],
-      datetime: ['eq', 'ne', 'gt', 'lt', 'ge', 'le', 'range'] }.freeze
+      datetime: ['eq', 'ne', 'gt', 'lt', 'ge', 'le', 'range'],
+      interval: ['range'] }.freeze
+  LABELS = {
+      'resource_id' => 'counts:columns.resourceId', 'version_no' => 'counts:columns.version',
+      'is_latest' => 'counts:columns.latest', 'event_type' => 'counts:eventType',
+      'user' => 'history:actor', 'created_at' => 'counts:columns.changedAt',
+      'thumbnail' => 'counts:columns.thumbnailDisplay',
+      'thumbnail_base' => 'counts:columns.thumbnailURL',
+      'title' => 'counts:columns.postTitle', 'url' => 'counts:columns.postURL',
+      'tags' => 'counts:columns.tags', 'tags_json' => 'counts:columns.tags',
+      'video_ms' => 'shared:labels.duration', 'name' => 'counts:columns.name',
+      'names' => 'counts:columns.names', 'category' => 'common:categoryLabel',
+      'aliases' => 'tags:aliases', 'deprecated' => 'counts:columns.deprecated',
+      'original_created_from' => 'counts:columns.originalFrom',
+      'original_created_before' => 'counts:columns.originalBefore',
+      'language_code' => 'counts:columns.language' }.freeze
+  CHILD_LABELS = {
+      'id' => 'counts:columns.resourceId', 'versionNo' => 'history:version',
+      'kind' => 'counts:columns.kind', 'name' => 'history:name',
+      'category' => 'common:categoryLabel', 'sections' => 'counts:columns.sections',
+      'names' => 'counts:columns.names', 'aliases' => 'tags:aliases',
+      'languageCode' => 'counts:columns.language',
+      'scriptCode' => 'history:nameChanges.script',
+      'autoGenerated' => 'history:nameChanges.automatic',
+      'tagId' => 'counts:attributes.tag_id', 'tagGroupId' => 'counts:resources.tag_groups',
+      'sectionName' => 'counts:attributes.section_name',
+      'description' => 'counts:attributes.description',
+      'children' => 'counts:attributes.children', 'profile' => 'counts:attributes.profile',
+      'path' => 'counts:attributes.path' }.freeze
 
   attr_reader :model, :keys, :fields, :resource
 
@@ -62,4 +90,57 @@ class CountsResourceDefinition
         operators: OPERATORS.fetch(type, []) }
     end
   end
+
+  def field_label(key) = LABELS.fetch(key, "counts:attributes.#{ key }")
+
+  def output_fields
+    content = case resource
+              when 'posts'
+                ['thumbnail', 'title', 'url', 'thumbnail_base', 'tags', 'parents', 'video_ms',
+                 'original_created_from', 'original_created_before']
+              when 'tags' then ['name', 'names', 'category', 'aliases', 'parents', 'deprecated']
+              else fields.keys - COMMON.keys
+              end
+    keys = ['resource_id', 'version_no', 'is_latest'] + (content - ['thumbnail']) +
+        ['event_type', 'user', 'created_at']
+    keys.unshift('thumbnail') if content.include?('thumbnail')
+    keys.map do |key|
+      label = if key == 'parents'
+                resource == 'tags' ? 'tags:parents' : 'shared:labels.parentPosts'
+              else field_label(key)
+              end
+      field = { key:, label: }
+      children = child_fields(key)
+      field[:children] = children if children.any?
+      field
+    end
+  end
+
+  def child_fields(key, depth = 4)
+    keys = case key
+           when 'tags' then ['id', 'versionNo', 'kind', 'name', 'category', 'sections', 'names']
+           when 'names' then ['languageCode', 'scriptCode', 'name', 'aliases', 'autoGenerated']
+           when 'aliases'
+             resource == 'tags' ? ['languageCode', 'name', 'scriptCode'] : ['name', 'scriptCode']
+           when 'parents' then resource == 'tags' ? ['id', 'name'] : ['id']
+           when 'members' then ['tagId', 'tagGroupId', 'versionNo']
+           when 'export_paths_json' then ['profile', 'path']
+           when 'placements', 'children'
+             scalar = ['sectionName', 'description', 'tagId', 'tagGroupId']
+             scalar + (depth > 0 ? ['children'] : [])
+           else []
+           end
+    keys.map do |child|
+      label = key == 'members' && child == 'tagId' ?
+          'counts:columns.resourceId' : CHILD_LABELS.fetch(child)
+      field = { key: child, label: }
+      children = child_fields(child, child == 'children' ? depth - 1 : depth)
+      # Language is attached to top-level aliases, not to aliases inside a language entry.
+      children = children.reject { _1[:key] == 'languageCode' } if child == 'aliases'
+      field[:children] = children if children.any?
+      field
+    end
+  end
+
+  def filter_metadata = @filter_metadata ||= CountsCondition.fields(self)
 end
diff --git a/backend/app/services/counts_table_export.rb b/backend/app/services/counts_table_export.rb
index e50d98b..87981b2 100644
--- a/backend/app/services/counts_table_export.rb
+++ b/backend/app/services/counts_table_export.rb
@@ -67,7 +67,9 @@ class CountsTableExport
           unless started
             metadata = page.except(:versions, :cells, :axis_labels, :column_values,
                 :row_headers, :column_headers, :pivot_totals).merge(
-                resource:, filters: @params.select { |key, _value| CountsTableQuery::KEYS.include?(key) ||
+                resource:, record_unit: @summary && format == 'json' ? 'pivot_cell' : 'row',
+                body_row_totals: 'once_per_logical_group', page_grand_total_repeated: false,
+                filters: @params.select { |key, _value| CountsTableQuery::KEYS.include?(key) ||
         key == 'measures' || QueryState.valid_key?(key) },
                 fields: @query.population.definition.metadata,
                 columns: @columns, column_labels: @headers,
diff --git a/backend/app/services/counts_table_query.rb b/backend/app/services/counts_table_query.rb
index 51093e2..21f7c56 100644
--- a/backend/app/services/counts_table_query.rb
+++ b/backend/app/services/counts_table_query.rb
@@ -41,17 +41,29 @@ class CountsTableQuery
 
   def call
     ApplicationRecord.transaction do
-      metadata.merge(mode == 'summary' ? summary : details)
+      result = metadata.merge(mode == 'summary' ? summary : details)
+      visible = mode == 'summary' ? result[:visible_output_count] : result[:count]
+      # A scalar result has one row regardless of private attributes or predicates.
+      public_count = result[:excluded_count].zero? || (mode == 'summary' && axes.rows.empty?)
+      result.merge(visible_output_count: visible,
+          output_count: public_count ? visible : nil,
+          output_count_scope: public_count ?
+              'before_authorisation' : 'unavailable_private_history',
+          output_count_unit: 'table_body_rows',
+          page_grand_total_repeated: mode == 'summary' && axes.rows.any? &&
+              result[:group_count] > limit)
     end
   end
 
   def metadata
-    { population_count_scope: 'all_recorded_versions', population_count: HistoryAccess.population_count(@definition.model),
-      page:, limit:, execution_at: population.at.iso8601(6), at: @params['at'].presence,
-      definition: population.history ? 'history' : 'latest',
-      timezone: population.timezone.identifier, rows: axes.rows, cols: axes.columns,
-      fields: @definition.metadata,
-      count: population.scope.except(:select).optimizer_hints('MAX_EXECUTION_TIME(10000)').count }
+    @population_counts ||= HistoryAccess.population_counts(@definition.model)
+    @population_counts.merge(
+        population_count_scope: 'all_recorded_versions',
+        page:, limit:, execution_at: population.at.iso8601(6), at: @params['at'].presence,
+        definition: population.history ? 'history' : 'latest',
+        timezone: population.timezone.identifier, rows: axes.rows, cols: axes.columns,
+        fields: @definition.metadata,
+        count: population.scope.except(:select).optimizer_hints('MAX_EXECUTION_TIME(10000)').count)
   end
 
   def summary
@@ -143,7 +155,9 @@ class CountsTableQuery
       column_headers = [{ values: [], kind: 'grand_total' }]
     end
     totals = CountsPivotTotals.new(population, axes, row_headers, column_headers).call
-    { group_count: total, column_values:, row_headers:, column_headers:, pivot_totals: totals,
+    { group_count: total,
+      visible_output_count: output_row_count(prefix, row_keys, row_depths, total),
+      column_values:, row_headers:, column_headers:, pivot_totals: totals,
       cells: records.map do |row|
         { values: axes.all.each_index.map { row["a#{ _1 }"] }, count: row['count'].to_i }
       end, axis_labels: axis_labels(records, column_values) }
@@ -192,6 +206,21 @@ class CountsTableQuery
 
   private
 
+  def output_row_count(prefix, row_keys, depths, total)
+    # With no row axes the table has exactly one body row, including the zero-count case.
+    return 1 if row_keys.empty?
+
+    subtotals = depths.map do |depth|
+      keys = row_keys.first(depth).join(', ')
+      "(SELECT COUNT(*) FROM (SELECT #{ keys } FROM cells GROUP BY #{ keys }) subtotal_rows)"
+    end
+    expressions = [total.to_s, '1'] + subtotals
+    @output_row_count ||= @connection.select_value(<<~SQL).to_i
+      #{ prefix }
+      SELECT /*+ MAX_EXECUTION_TIME(10000) */ #{ expressions.join(' + ') } AS output_rows
+    SQL
+  end
+
   def locale = @locale ||= Locale.find_by!(code: @params.fetch('locale', 'ja'))
 
   def limited_columns(prefix)
diff --git a/frontend/src/App.tsx b/frontend/src/App.tsx
index dc27053..a46f65f 100644
--- a/frontend/src/App.tsx
+++ b/frontend/src/App.tsx
@@ -261,6 +261,8 @@ const RoutedApp = ({ locales }: { locales: AvailableLocale[] }) => {
   const locale = useLocale ()
   const route = resolvePageRoute (location.pathname)
   const robots = route?.route.handle?.robots
+  const pagePath = unlocalisedPath (location.pathname)
+  const countsPage = pagePath === '/counts' || pagePath.startsWith ('/counts/')
   const switchLocale = async (targetLocale: LocaleCode): Promise<string> => {
     const resolve = route?.route.handle?.switchLocale
     return (resolve != null && route != null)
@@ -377,7 +379,7 @@ const RoutedApp = ({ locales }: { locales: AvailableLocale[] }) => {
 	      }>
 	    <LayoutGroup>
 	      <motion.div
-		  layout={animationMode === 'off' ? false : 'position'}
+		  layout={(animationMode === 'off' || countsPage) ? false : 'position'}
 		  transition={{ layout: appLayoutTransition }}
 		  className="relative flex h-dvh w-full flex-col overflow-y-hidden">
 		<TopNav user={user} locales={locales} resolveLocaleSwitch={switchLocale}/>
diff --git a/frontend/src/components/counts/CountsAdditionalConditions.tsx b/frontend/src/components/counts/CountsAdditionalConditions.tsx
index 4ce91a1..8a61509 100644
--- a/frontend/src/components/counts/CountsAdditionalConditions.tsx
+++ b/frontend/src/components/counts/CountsAdditionalConditions.tsx
@@ -22,7 +22,9 @@ const ConditionEditor = (
 	save: (condition: CountsCondition) => void },
 ) => {
   const { label, message } = useUITranslation ('counts')
-  const fields = countsFilterFields (definition)
+  const fields = definition.filterFields ?? definition.fields
+  const fieldName = (key: string) => (fields.find (item => item.key === key)?.labels
+      ?? [countsFieldLabel (key)]).map (key => message (key).text).join (' › ')
   const [condition, setCondition] = useState<CountsCondition> (() => {
     const next = { ...initial, field: initial?.field ?? 'resource_id',
 	operator: initial?.operator ?? 'eq' }
@@ -30,7 +32,7 @@ const ConditionEditor = (
     return next
   })
   const { field, operator } = condition
-  const operators = definition.fields.find (item => item.key === field)?.operators ?? []
+  const operators = fields.find (item => item.key === field)?.operators ?? []
   useEffect (() => {
     controls.setActions ([{ label: label (initial == null ? 'add' : 'shared:actions.edit'),
 	onSelect: () => save (condition) }])
@@ -39,11 +41,11 @@ const ConditionEditor = (
     <select value={field} aria-label={message ('field').text} className={inputClass ()}
 	onChange={event => {
 	  const field = event.target.value
-	  const operator = definition.fields.find (item => item.key === field)?.operators[0]
+	  const operator = fields.find (item => item.key === field)?.operators[0]
 	  if (operator != null) setCondition ({ field, operator })
 	}}>
-      {Object.keys (fields).filter (key => fields[key] !== 'json').map (key => (
-          <option key={key} value={key}>{message (countsFieldLabel (key)).text}</option>))}
+      {fields.filter (field => field.operators.length > 0).map (field => (
+	  <option key={field.key} value={field.key}>{fieldName (field.key)}</option>))}
     </select>
     <select value={operator} aria-label={message ('operator').text} className={inputClass ()}
 	onChange={event => setCondition (previous => {
@@ -68,6 +70,9 @@ const CountsAdditionalConditions = ({ params, update }: {
   const definition = useCountsDefinition ()
   const dialogue = useDialogue ()
   const conditions = readCountState<CountsCondition[]> (params, 'conditions', [])
+  const metadata = definition.filterFields ?? definition.fields
+  const fieldName = (key: string) => (metadata.find (item => item.key === key)?.labels
+      ?? [countsFieldLabel (key)]).map (key => message (key).text).join (' › ')
   const write = (next: CountsCondition[]) => update ('conditions', encodeCountState ('conditions', next))
   const edit = (index?: number) => {
     const initial = index == null ? undefined : conditions[index]
@@ -81,37 +86,45 @@ const CountsAdditionalConditions = ({ params, update }: {
   }
   const patch = (index: number, change: Partial<CountsCondition>) => write (
       conditions.map ((item, position) => position === index ? { ...item, ...change } : item))
+  const valueInput = (condition: CountsCondition, index: number, key: 'value' | 'end') => {
+    const type = countsFilterFields (definition)[condition.field]
+    const aria = message (key === 'end' ? 'through' : 'value')
+    if (type === 'boolean' || condition.field === 'event_type')
+    {
+      const options: string[] = type === 'boolean' ? ['true', 'false'] : [...countsEventTypes]
+      const namespace = type === 'boolean' ? 'truthValues' : 'events'
+      return <select key={key} value={condition[key] ?? ''} disabled={condition.blank}
+          className={inputClass (false, 'w-36 py-1')} aria-label={aria.text}
+          onChange={event => patch (index, { [key]: event.target.value })}>
+        <option value=""/>
+        {options.map (value => <option key={value} value={value}
+            lang={message (`${namespace}.${value}`).language}>
+          {message (`${namespace}.${value}`).text}</option>)}
+      </select>
+    }
+    if (type === 'datetime')
+      return <DateTimeField precision="second" key={key}
+          value={condition[key] ?? ''} disabled={condition.blank}
+          aria-label={aria.text} lang={aria.language}
+          onChange={value => patch (index, { [key]: value ?? '' })}/>
+    return <input key={key} value={condition[key] ?? ''} disabled={condition.blank}
+        type={(type === 'integer' || type === 'interval') ? 'number' : 'text'}
+        className={inputClass (false, 'w-36 py-1')}
+        aria-label={aria.text} lang={aria.language}
+        onChange={event => patch (index, { [key]: event.target.value })}/>
+  }
   return <fieldset className="space-y-1">
     <legend className="flex items-center gap-2">{label ('additionalConditions')}
       <Button type="button" variant="outline" size="sm" onClick={() => edit ()}>
         {label ('add')}</Button></legend>
     {conditions.map ((condition, index) => {
-      const datetime = countsFilterFields (definition)[condition.field] === 'datetime'
       return <div key={index} className="flex flex-wrap items-center gap-1">
         <button type="button" onClick={() => edit (index)}>
-	  {label (countsFieldLabel (condition.field))}
+	  {fieldName (condition.field)}
 	  {' · '}{label (`operators.${condition.operator}`)}
         </button>
         {(condition.operator === 'range' ? ['value', 'end'] as const : ['value'] as const)
-	    .map (key => condition.field === 'event_type' ? (
-		<select key={key} value={condition[key] ?? ''} disabled={condition.blank}
-		    className={inputClass (false, 'w-36 py-1')}
-		    aria-label={message ('value').text}
-		    onChange={event => patch (index, { [key]: event.target.value })}>
-		  <option value=""/>
-		  {condition[key] && !countsEventTypes.some (event => event === condition[key])
-		      && <option value={condition[key]}>{condition[key]}</option>}
-		  {countsEventTypes.map (event => <option key={event} value={event}
-		      lang={message (`events.${event}`).language}>
-		    {message (`events.${event}`).text}</option>)}
-		</select>) : (datetime ? <DateTimeField precision="second" key={key}
-                value={condition[key] ?? ''} disabled={condition.blank}
-                aria-label={message (key === 'end' ? 'through' : 'value').text}
-                onChange={value => patch (index, { [key]: value ?? '' })}/> : (
-                <input key={key} value={condition[key] ?? ''} disabled={condition.blank}
-                    className={inputClass (false, 'w-36 py-1')}
-                    aria-label={message ('value').text}
-		    onChange={event => patch (index, { [key]: event.target.value })}/>)))}
+	    .map (key => valueInput (condition, index, key))}
         <label className="inline-flex items-center gap-1">
           <input type="checkbox" checked={condition.blank ?? false}
               onChange={event => patch (index, { blank: event.target.checked })}/>
diff --git a/frontend/src/components/counts/CountsControls.tsx b/frontend/src/components/counts/CountsControls.tsx
index 3ac93ee..3709184 100644
--- a/frontend/src/components/counts/CountsControls.tsx
+++ b/frontend/src/components/counts/CountsControls.tsx
@@ -26,8 +26,9 @@ import type { CountsResource } from '@/lib/counts'
 
 const CountsControls = (
     { resource, applied, open, setOpen, execute, displayJSON, displayRowNumbers,
-      displayThumbnail, reorder, actions }: {
+      displayThumbnail, reorder, actions, pending = false }: {
         resource: CountsResource; applied: URLSearchParams; open: boolean
+        pending?: boolean
         setOpen: (open: boolean) => void
         execute: (params: URLSearchParams) => void
         displayJSON: (enabled: boolean) => void
@@ -106,9 +107,9 @@ const CountsControls = (
   })
   return <form className="shrink-0" onSubmit={event => {
     event.preventDefault ()
+    if (pending) return
     const next = new URLSearchParams (draft)
     next.delete ('page')
-    next.delete ('execution_at')
     execute (normaliseCountsParams (resource, next, definition))
   }}>
     {!history && <div className="flex flex-wrap items-center gap-2 border-b pb-1
@@ -130,7 +131,8 @@ const CountsControls = (
       </div>
     </div>}
     <div className="flex flex-wrap items-center gap-2 border-b py-1 dark:border-slate-700">
-      <Button type="submit" size="sm">{label ('run')}</Button>
+      <Button type="submit" size="sm" aria-disabled={pending}
+          className="aria-disabled:opacity-50">{label ('run')}</Button>
       <Button type="button" size="sm" variant="outline" aria-expanded={open}
           aria-controls={id} onClick={() => setOpen (!open)}>
         {label ('conditions')}<span aria-hidden className="inline-block" style={{
diff --git a/frontend/src/components/layout/MainArea.tsx b/frontend/src/components/layout/MainArea.tsx
index 268f015..ae3d9c7 100644
--- a/frontend/src/components/layout/MainArea.tsx
+++ b/frontend/src/components/layout/MainArea.tsx
@@ -8,10 +8,11 @@ import type { FC, ReactNode } from 'react'
 
 type Props = {
     children:   ReactNode
-    className?: string }
+    className?: string
+    animateLayout?: boolean }
 
 
-const MainArea: FC<Props> = ({ children, className }) => {
+const MainArea: FC<Props> = ({ children, className, animateLayout = true }) => {
   const behaviourSettings = useClientBehaviourSettings ()
   const animationMode = behaviourSettings.animation ?? 'normal'
   const layoutTransition = clientAnimationTransition (
@@ -23,7 +24,7 @@ const MainArea: FC<Props> = ({ children, className }) => {
       <motion.main
 	  transition={{ layout: layoutTransition }}
 	  className={cn ('flex-1 overflow-y-auto p-4', className)}
-	  layout={animationMode === 'off' ? false : 'position'}>
+	  layout={(animationMode === 'off' || !animateLayout) ? false : 'position'}>
 	{children}
       </motion.main>)
 }
diff --git a/frontend/src/components/layout/SidebarComponent.tsx b/frontend/src/components/layout/SidebarComponent.tsx
index 762e567..6e2b29c 100644
--- a/frontend/src/components/layout/SidebarComponent.tsx
+++ b/frontend/src/components/layout/SidebarComponent.tsx
@@ -16,6 +16,7 @@ type Props = {
     className?:    string
     maxWidth?:     number
     maxWidthRatio?: number
+    animateLayout?: boolean
     onWidthChange?: (width: number) => void
     sidebarKey:    string
     side?:         SidebarSide }
@@ -69,6 +70,7 @@ const SidebarComponent: FC<Props> = ({
     className,
     maxWidth,
     maxWidthRatio,
+    animateLayout = true,
     onWidthChange,
     sidebarKey,
     side = 'left',
@@ -316,7 +318,7 @@ const SidebarComponent: FC<Props> = ({
   return (
       <motion.div
 	  ref={rootRef}
-	  layout={animationMode === 'off' ? false : 'position'}
+	  layout={(animationMode === 'off' || !animateLayout) ? false : 'position'}
 	  transition={{ layout: layoutTransition }}
 	  style={style}
 	  className={cn (
diff --git a/frontend/src/lib/counts.ts b/frontend/src/lib/counts.ts
index 01b9afc..cfe7b15 100644
--- a/frontend/src/lib/counts.ts
+++ b/frontend/src/lib/counts.ts
@@ -61,6 +61,10 @@ export type CountsPivotHeader = { values: (string | number | null)[]
     kind: 'data' | 'subtotal' | 'grand_total' }
 export type CountsResult = {
     populationCount?: number
+    excludedCount?: number
+    outputCount?: number | null
+    visibleOutputCount?: number
+    outputCountScope?: 'before_authorisation' | 'unavailable_private_history'
     populationCountScope?: string
     rowHeaders?: CountsPivotHeader[]
     columnHeaders?: CountsPivotHeader[]
@@ -148,7 +152,7 @@ const nested: Partial<Record<CountColumn, CountField[]>> = {
 export const columnsForCounts = (
     resource: CountsResource,
     definition?: CountsDefinition,
-): CountColumn[] => [
+): CountColumn[] => definition?.outputFields?.map (field => field.key) ?? [
     ...(resource === 'posts' ? ['thumbnail'] : []),
     'resource_id', 'version_no', 'is_latest',
     ...(resource === 'posts'
@@ -165,7 +169,8 @@ export const columnsForCounts = (
 export const fieldsForCounts = (
     resource: CountsResource,
     definition?: CountsDefinition,
-): CountField[] => columnsForCounts (resource, definition).map (key => ({
+): CountField[] => definition?.outputFields
+    ?? columnsForCounts (resource, definition).map (key => ({
 	key,
 	label: (key === 'parents' && resource === 'tags') ? 'tags:parents'
             : (countColumns[key] ?? countsFieldLabel (key)),
@@ -303,6 +308,17 @@ export const defaultCountsMode = (definition: string | null): 'summary' | 'detai
     definition === 'history' ? 'details' : 'summary'
 
 
+export const countsDefinitionParams = (
+    definition: 'latest' | 'history',
+    previous: URLSearchParams,
+): URLSearchParams => {
+  const next = new URLSearchParams ({ definition, mode: defaultCountsMode (definition) })
+  for (const key of ['timezone', 'row_numbers'])
+    if (previous.has (key)) next.set (key, previous.get (key)!)
+  return next
+}
+
+
 export const normaliseCountsParams = (
     resource: CountsResource,
     source: URLSearchParams,
@@ -311,7 +327,8 @@ export const normaliseCountsParams = (
   const params = new URLSearchParams (source)
   if (!params.has ('definition'))
     params.set ('definition', params.get ('basis') === 'history' ? 'history' : 'latest')
-  if (!params.has ('current')) params.set ('current', params.get ('at') ? '0' : '1')
+  if (params.get ('definition') === 'latest' && !params.has ('current'))
+    params.set ('current', params.get ('at') ? '0' : '1')
   const legacy = params.get ('mode')
   if (['state', 'trend', 'snapshot'].includes (legacy ?? ''))
     params.set ('mode', legacy === 'snapshot' ? 'details' : 'summary')
@@ -392,8 +409,9 @@ export const fetchCounts = (
     resource: CountsResource,
     params: URLSearchParams,
     locale: LocaleCode,
+    signal?: AbortSignal,
 ): Promise<CountsResult> => apiGet ('/counts/query', {
-    locale, params: { ...Object.fromEntries (countsRequestParams (params)), resource } })
+    locale, signal, params: { ...Object.fromEntries (countsRequestParams (params)), resource } })
 
 
 
diff --git a/frontend/src/lib/countsDefinitions.ts b/frontend/src/lib/countsDefinitions.ts
index fc160d1..c49652a 100644
--- a/frontend/src/lib/countsDefinitions.ts
+++ b/frontend/src/lib/countsDefinitions.ts
@@ -9,14 +9,18 @@ import type { CountField, CountsResource } from '@/lib/counts'
 export type CountsAxis = { field: string; grain?: string }
 export type CountsCondition = {
     field: string; operator: string; value?: string; end?: string; blank?: boolean }
-export type CountsFieldType = 'string' | 'integer' | 'datetime' | 'enum' | 'json' | 'boolean'
+export type CountsFieldType = 'string' | 'integer' | 'datetime' | 'enum'
+    | 'json' | 'boolean' | 'interval'
 
 export const countsResources: CountsResource[] = [
     'posts', 'tags', 'nico_tags', 'tag_descriptions', 'tag_groups', 'materials']
 export type CountsFieldMetadata = {
-    key: string; type: CountsFieldType; nullable: boolean; operators: string[] }
+    key: string; type: CountsFieldType; nullable: boolean; operators: string[]
+    labels?: string[]; multiple?: boolean }
 export type CountsDefinition = {
     fields: CountsFieldMetadata[]
+    outputFields?: CountField[]
+    filterFields?: CountsFieldMetadata[]
     defaults?: { definition: string; mode: string; params: { key: string; value: string }[] }[]
     axes: { latest: string[]; history: string[] }
     grains: string[] }
@@ -38,7 +42,7 @@ export const fetchCountsDefinition = (resource: CountsResource): Promise<CountsD
 export const countsFilterFields = (
     definition: CountsDefinition,
 ): Record<string, CountsFieldType> => Object.fromEntries (
-    definition.fields.map (field => [field.key, field.type]))
+    (definition.filterFields ?? definition.fields).map (field => [field.key, field.type]))
 
 
 export const countsFieldLabel = (key: string): string => {
diff --git a/frontend/src/locales/ja/counts.json b/frontend/src/locales/ja/counts.json
index 8aac6f0..43816e7 100644
--- a/frontend/src/locales/ja/counts.json
+++ b/frontend/src/locales/ja/counts.json
@@ -68,6 +68,10 @@
     "limit": "表示件数"
   },
   "latestOnly": "最新のみ",
+  "truthValues": {
+    "true": "真",
+    "false": "偽"
+  },
   "boolean": {
     "true": "はい",
     "false": "いいえ"
@@ -168,6 +172,8 @@
   "changedField": "変更項目",
   "eventType": "異動区分",
   "count": "件数",
+  "outputTotal": "綜件数：{{value}} 件",
+  "excludedRecords": "（閲覧権限のないレコード {{count}} 件が除外されました）",
   "recordTotal": "閲覧可能件数：{{count}}",
   "grain": "粒度",
   "grains": {
diff --git a/frontend/src/pages/CountsResourcePage.tsx b/frontend/src/pages/CountsResourcePage.tsx
index ffd9e50..20523ba 100644
--- a/frontend/src/pages/CountsResourcePage.tsx
+++ b/frontend/src/pages/CountsResourcePage.tsx
@@ -15,12 +15,12 @@ import Pagination from '@/components/common/Pagination'
 import MainArea from '@/components/layout/MainArea'
 import SidebarComponent from '@/components/layout/SidebarComponent'
 import { Button } from '@/components/ui/button'
-import { countsRequestParams, defaultCountsMode, countsExportPayload, fieldsForCounts, fetchCounts,
+import { countsRequestParams, countsDefinitionParams, countsExportPayload, fieldsForCounts, fetchCounts,
 	 isCountsState, normaliseCountsParams, selectedCountColumns } from '@/lib/counts'
 import { countsExportLabels } from '@/lib/countsDisplay'
 import { CountsDefinitionContext, countsAxisFields, countsAxisLabel,
 	 countsResources, countsFieldLabel,
-	 fetchCountsDefinition, useCountsDefinition }
+	 fetchCountsDefinition }
     from '@/lib/countsDefinitions'
 import { countsKeys } from '@/lib/queryKeys'
 import { cn } from '@/lib/utils'
@@ -31,19 +31,44 @@ import { useUITranslation } from '@/lib/useUITranslation'
 
 import { setCountState, readCountState } from '@/lib/queryState'
 
-import type { CountsAxis } from '@/lib/countsDefinitions'
+import type { CountsAxis, CountsDefinition } from '@/lib/countsDefinitions'
 
 import type { CountsResource } from '@/lib/counts'
 
+type PendingCountsRun = {
+    key: ReturnType<typeof countsKeys.index>
+    origin: string
+    params: URLSearchParams
+    target?: string }
 
-const CountsResourceContent = ({ resource }: { resource: CountsResource }) => {
-  const definition = useCountsDefinition ()
+
+const CountsResourceContent = (
+    { resource, definition, definitionError }: {
+        resource: CountsResource; definition?: CountsDefinition; definitionError: boolean },
+) => {
   const queryClient = useQueryClient ()
   const [source, setParams] = useSearchParams ()
+  const [timezone, setTimezone] = useState<string | null> (null)
+  useEffect (() => {
+    setTimezone (Intl.DateTimeFormat ().resolvedOptions ().timeZone)
+  }, [])
   const params = normaliseCountsParams (resource, source, definition)
+  if (!params.has ('timezone') && timezone != null) params.set ('timezone', timezone)
   const canonical = params.toString ()
   const request = countsRequestParams (params)
   const [open, setOpen] = useState (false)
+  const controlsArea = useRef<HTMLDivElement> (null)
+  const [controlsHeight, setControlsHeight] = useState (80)
+  useEffect (() => {
+    const node = controlsArea.current
+    if (definition == null || node == null) return
+    const measure = () => setControlsHeight (node.getBoundingClientRect ().height)
+    measure ()
+    if (typeof ResizeObserver === 'undefined') return
+    const observer = new ResizeObserver (measure)
+    observer.observe (node)
+    return () => observer.disconnect ()
+  }, [definition])
   const [sidebarOpen, setSidebarOpen] = useState (false)
   const [expanded, setExpanded] = useState (() => new Set<string> ([resource]))
   const motion = useClientMotion ()
@@ -57,42 +82,138 @@ const CountsResourceContent = ({ resource }: { resource: CountsResource }) => {
   const state = isCountsState (params)
   const cacheParams = new URLSearchParams (request)
   cacheParams.set ('definition', state ? 'latest' : 'history')
+  const [running, setRunning] = useState (false)
+  const [runError, setRunError] = useState (false)
+  const pendingRun = useRef<PendingCountsRun | null> (null)
+  const applied = useRef (params)
+  const retainedParams = useRef (params)
+  const requestKey = request.toString ()
   const [exporting, setExporting] = useState (false)
   const exportInFlight = useRef (false)
   const [exportError, setExportError] = useState (false)
   const { data, dataUpdatedAt, isFetching, isPending, isError,
-      isPlaceholderData, refetch } = useQuery ({
-      enabled: params.has ('timezone'),
+      isPlaceholderData } = useQuery ({
+      enabled: definition != null && params.has ('timezone') && !running,
       staleTime: params.has ('execution_at') ? 5 * 60 * 1000 : 0,
       queryKey: countsKeys.index (resource, cacheParams.toString (), locale),
-      queryFn: () => fetchCounts (resource, params, locale), retry: false,
-      placeholderData: (previous, query) => {
-	const previousParams = new URLSearchParams (String (query?.queryKey[3] ?? ''))
-	return (query?.queryKey[1] === resource && query?.queryKey[2] === locale
-	    && previousParams.get ('mode') === mode
-	    && previousParams.get ('rows') === params.get ('rows')
-            && previousParams.get ('cols') === params.get ('cols')
-	    && previousParams.get ('definition') === cacheParams.get ('definition'))
-	    ? previous : undefined
-      } })
+      queryFn: ({ signal }) => fetchCounts (resource, params, locale, signal), retry: false,
+      placeholderData: (previous, query) =>
+          (query?.queryKey[1] === resource && query?.queryKey[2] === locale
+              && queryClient.getQueryData (query.queryKey) === previous)
+          ? previous : undefined })
 
   useEffect (() => {
+    applied.current = params
+    if (data != null && !isPlaceholderData && !isError) retainedParams.current = params
+    const pending = pendingRun.current
+    if (pending == null) return
+    if (pending.target === canonical)
+    {
+      pendingRun.current = null
+      setRunning (false)
+    }
+    else if (pending.origin !== requestKey)
+    {
+      pendingRun.current = null
+      void queryClient.cancelQueries ({ queryKey: pending.key, exact: true })
+      setRunning (false)
+    }
+  }, [canonical, data, isError, isPlaceholderData, params, queryClient, requestKey])
+
+  useEffect (() => {
+    setRunning (false)
+    setRunError (false)
+    return () => {
+      const pending = pendingRun.current
+      pendingRun.current = null
+      if (pending != null)
+        void queryClient.cancelQueries ({ queryKey: pending.key, exact: true })
+    }
+  }, [locale, queryClient, resource])
+
+  useEffect (() => {
+    if (running || data == null || isPlaceholderData || isFetching || isError
+        || !params.has ('timezone')) return
     const next = new URLSearchParams (canonical)
-    if (!next.has ('timezone'))
-      next.set ('timezone', Intl.DateTimeFormat ().resolvedOptions ().timeZone)
-    if (data?.executionAt != null && !isPlaceholderData && !isFetching && !isError
-	&& params.has ('timezone') && !params.has ('execution_at'))
+    if (data.executionAt != null && !params.has ('execution_at'))
     {
       next.set ('execution_at', data.executionAt)
-      // Pin the response under its server-confirmed time before changing the URL.
+      // Commit initial defaults, timezone and server time together after acquisition.
       queryClient.setQueryData (
-	  countsKeys.index (resource, countsRequestParams (next).toString (), locale),
-	  data, { updatedAt: dataUpdatedAt })
+          countsKeys.index (resource, countsRequestParams (next).toString (), locale),
+          data, { updatedAt: dataUpdatedAt })
     }
     if (source.toString () !== next.toString ())
-      setParams (next, { replace: true })
+      setParams (next, { replace: true, preventScrollReset: true })
   }, [canonical, data, dataUpdatedAt, isError, isFetching, isPlaceholderData,
-      locale, params, queryClient, resource, setParams, source])
+      locale, params, queryClient, resource, running, setParams, source])
+
+
+  const execute = async (draft: URLSearchParams) => {
+    if (pendingRun.current != null || definition == null) return
+    const next = normaliseCountsParams (resource, draft, definition)
+    next.delete ('execution_at')
+    if (!next.has ('timezone'))
+      next.set ('timezone', Intl.DateTimeFormat ().resolvedOptions ().timeZone)
+    const pending: PendingCountsRun = {
+        key: countsKeys.index (resource, countsRequestParams (next).toString (), locale),
+        origin: requestKey, params: new URLSearchParams (next) }
+    const previous = new URLSearchParams (params)
+    pendingRun.current = pending
+    setRunError (false)
+    setRunning (true)
+    try
+    {
+      const result = await queryClient.fetchQuery ({ queryKey: pending.key,
+          queryFn: ({ signal }) => fetchCounts (resource, next, locale, signal),
+          staleTime: 0, retry: false })
+      if (pendingRun.current !== pending) return
+      if (result.executionAt == null) throw new Error ('Missing Counts execution time')
+      // Preserve presentation changes made while this execution was in flight.
+      for (const key of ['columns', 'children', 'child_sort', 'order', 'nested_json', 'row_numbers'])
+      {
+        if (previous.get (key) === applied.current.get (key)) continue
+        if (key === 'columns')
+        {
+          const columns = selectedCountColumns (resource, next, definition)
+              .filter (column => column !== 'thumbnail')
+          const thumbnail = selectedCountColumns (resource, applied.current, definition)
+              .includes ('thumbnail')
+          next.set ('columns', (thumbnail ? ['thumbnail', ...columns] : columns).join (' '))
+          continue
+        }
+        next.delete (key)
+        for (const value of applied.current.getAll (key)) next.append (key, value)
+      }
+      const committed = normaliseCountsParams (resource, next, definition)
+      committed.set ('execution_at', result.executionAt)
+      queryClient.setQueryData (
+          countsKeys.index (resource, countsRequestParams (committed).toString (), locale), result)
+      pending.target = committed.toString ()
+      // Commit only after the complete result is available under the final URL's key.
+      if (pending.target === canonical)
+      {
+        pendingRun.current = null
+        setRunning (false)
+      }
+      else setParams (committed, { preventScrollReset: true })
+    }
+    catch
+    {
+      if (pendingRun.current !== pending) return
+      pendingRun.current = null
+      setRunning (false)
+      setRunError (true)
+    }
+  }
+  const resultParams = isPlaceholderData ? retainedParams.current : params
+  const resultMode = resultParams.get ('mode') ?? 'summary'
+  const waiting = running || (!definitionError && (definition == null
+      || isPending || isFetching || isPlaceholderData
+      || (!params.has ('execution_at') && !isError)))
+  const loadingParams = pendingRun.current?.params ?? params
+  const compatible = data != null && ['definition', 'mode', 'rows', 'cols'].every (
+      key => loadingParams.get (key) === resultParams.get (key))
 
 
   const update = (key: string, value: string, extra?: Record<string, string>) => {
@@ -110,7 +231,7 @@ const CountsResourceContent = ({ resource }: { resource: CountsResource }) => {
     setParams (next)
   }
   const download = async (format: 'csv' | 'json') => {
-    if (exportInFlight.current) return
+    if (exportInFlight.current || pendingRun.current != null || definition == null) return
     exportInFlight.current = true
     setExporting (true)
     setExportError (false)
@@ -160,7 +281,7 @@ const CountsResourceContent = ({ resource }: { resource: CountsResource }) => {
 	  <Button type="button" variant="ghost" size="sm" className="shrink-0 md:hidden"
 	      aria-expanded={sidebarOpen} aria-controls="counts-targets"
 	      onClick={() => setSidebarOpen (!sidebarOpen)}>{label ('target')}</Button>
-	  <SidebarComponent sidebarKey="counts" maxWidthRatio={.5}
+	  <SidebarComponent sidebarKey="counts" maxWidthRatio={.5} animateLayout={false}
 	      className={cn ('md:block', !sidebarOpen && 'hidden')}>
 	    <nav id="counts-targets" aria-label={message ('target').text}
 		lang={message ('target').language}>
@@ -184,11 +305,8 @@ const CountsResourceContent = ({ resource }: { resource: CountsResource }) => {
                   </button>
                   <AnimatedCollapse open={expanded.has (target)} id={`counts-definition-${target}`}>
                   <ul className="ml-3">
-                    {['latest', 'history'].map (definition => {
-		      const next = new URLSearchParams ({
-			  definition, mode: defaultCountsMode (definition) })
-		      for (const key of ['timezone', 'at', 'current', 'row_numbers'])
-                        if (params.get (key)) next.set (key, params.get (key)!)
+                    {(['latest', 'history'] as const).map (definition => {
+                      const next = countsDefinitionParams (definition, params)
                       const active = target === resource
                           && params.get ('definition') === definition
                       return <li key={definition}><PrefetchLink
@@ -203,11 +321,13 @@ const CountsResourceContent = ({ resource }: { resource: CountsResource }) => {
 	      </ul>
 	    </nav>
 	  </SidebarComponent>
-	  <MainArea className="flex min-h-0 min-w-0 flex-col p-2">
+	  <MainArea animateLayout={false} className="flex min-h-0 min-w-0 flex-col p-2">
 	    <PageTitle className="mb-1 text-base">{label (`titles.${resource}`)}</PageTitle>
-	    <div className="shrink-0">
-	      <CountsControls
+	    <div ref={controlsArea} className="shrink-0"
+		style={{ minHeight: definition == null ? controlsHeight : undefined }}>
+	      {definition != null && <CountsControls key={`${resource}:${params.get ('definition')}`}
 		  resource={resource} applied={params}
+		  pending={running || isFetching || !params.has ('execution_at')}
 		  open={open} setOpen={setOpen}
 		  reorder={value => update ('order', value)}
 		  displayJSON={enabled => update ('nested_json', enabled ? '1' : '0')}
@@ -217,36 +337,48 @@ const CountsResourceContent = ({ resource }: { resource: CountsResource }) => {
 			.filter (column => column !== 'thumbnail')
 		    update ('columns', (enabled ? ['thumbnail', ...columns] : columns).join (' '))
 		  }}
-		  execute={next => {
-		    if (next.toString () === canonical) void refetch ()
-		    else setParams (next)
-		  }} actions={<div className="ml-auto flex shrink-0 items-center gap-2">
+		  execute={next => void execute (next)}
+		  actions={<div className="ml-auto flex shrink-0 items-center gap-2">
 		    {(['csv', 'json'] as const).map (format => <Button key={format}
 			type="button" variant="outline" size="sm"
 			disabled={data == null || isError || isPlaceholderData
-			    || exporting || !params.get ('execution_at')}
+			    || running || isFetching || exporting || !params.get ('execution_at')}
 			onClick={() => void download (format)}>
 		      {label (`exportFormats.${format}`)}</Button>)}
-		  </div>}/>
+		  </div>}/>}
 
 	      {exportError && <p role="alert">{label ('common:fetchError')}</p>}
 	    </div>
-	    {isPending && <p>{label ('shared:messages.loadingEllipsis')}</p>}
-	    {isError && <p role="alert">{label ('common:fetchError')}</p>}
-	    {data != null && <>
-              <p className="my-1 flex flex-wrap gap-x-3 text-xs">
-                <span>{label ('recordTotal', { count: data.count })}</span>
-                {data.populationCount != null && <span>{label ('total', {
-                    count: data.populationCount })}</span>}
-              </p>
-	      {mode === 'summary' ? <CountsSummaryResults resource={resource}
-		  data={data} params={params}
-		  pending={isPlaceholderData} update={update}/> : (
-		  <CountsResults resource={resource} data={data} params={params}
-		      pending={isPlaceholderData} update={update}/>)}
+	    {(definitionError || isError || runError) && <p role="alert">{label ('common:fetchError')}</p>}
+	    <div className="relative flex min-h-0 flex-1 flex-col overflow-hidden"
+		aria-busy={waiting}>
+	      <div inert={waiting} aria-hidden={waiting || undefined}
+		  className={cn ('flex min-h-0 flex-1 flex-col',
+		      waiting && (compatible ? 'pointer-events-none opacity-40' : 'invisible'))}>
+	    {definition != null && data != null && <>
+              {data.excludedCount != null && (
+                  <p className="my-1 flex flex-wrap items-baseline gap-x-2 text-sm">
+                    <span>{label ('outputTotal', { value: data.outputCount ?? '—' })}</span>
+                    <span className="text-xs text-slate-500 dark:text-slate-400">
+                      {label ('excludedRecords', { count: data.excludedCount })}</span>
+                  </p>)}
+	      {resultMode === 'summary' ? <CountsSummaryResults resource={resource}
+		  data={data} params={resultParams}
+		  pending={waiting} update={update}/> : (
+		  <CountsResults resource={resource} data={data} params={resultParams}
+		      pending={waiting} update={update}/>)}
 	      <Pagination page={data.page} totalPages={Math.ceil (
-		  (mode === 'summary' ? data.groupCount ?? 0 : data.count) / data.limit)}/>
+		  (resultMode === 'summary' ? data.groupCount ?? 0 : data.count) / data.limit)}/>
 	    </>}
+              </div>
+              {waiting && <div role="status" aria-live="polite"
+                  className="pointer-events-none absolute inset-0 flex items-center justify-center">
+                <span className="rounded border border-slate-300 bg-white px-2 py-1
+                    text-sm text-slate-900 dark:border-slate-600
+                    dark:bg-slate-950 dark:text-slate-100">
+                  {label ('shared:messages.loadingEllipsis')}</span>
+              </div>}
+            </div>
 	  </MainArea>
 	</div>
       </CountsTableLayout>)
@@ -254,14 +386,11 @@ const CountsResourceContent = ({ resource }: { resource: CountsResource }) => {
 
 
 const CountsResourcePage = ({ resource }: { resource: CountsResource }) => {
-  const { label } = useUITranslation ('counts')
   const { data, isError } = useQuery ({
       queryKey: countsKeys.definition (resource),
       queryFn: () => fetchCountsDefinition (resource), staleTime: Infinity })
-  if (data == null) return <p>{label (
-      isError ? 'common:fetchError' : 'shared:messages.loadingEllipsis')}</p>
-  return <CountsDefinitionContext.Provider value={data}>
-    <CountsResourceContent resource={resource}/>
+  return <CountsDefinitionContext.Provider value={data ?? null}>
+    <CountsResourceContent resource={resource} definition={data} definitionError={isError}/>
   </CountsDefinitionContext.Provider>
 }