diff --git a/backend/app/controllers/counts_tables_controller.rb b/backend/app/controllers/counts_tables_controller.rb
index f3620c3..df0c287 100644
--- a/backend/app/controllers/counts_tables_controller.rb
+++ b/backend/app/controllers/counts_tables_controller.rb
@@ -20,4 +20,12 @@ class CountsTablesController < ApplicationController
   rescue ArgumentError, TypeError, KeyError, JSON::ParserError
     head :bad_request
   end
+
+  def candidates
+    resolve_locale!
+    render json: CountsCandidates.new(request.query_parameters.merge(
+        'resource' => request.path_parameters[:resource])).call
+  rescue ArgumentError, TypeError, KeyError
+    head :bad_request
+  end
 end
diff --git a/backend/app/services/counts_candidates.rb b/backend/app/services/counts_candidates.rb
new file mode 100644
index 0000000..eebf002
--- /dev/null
+++ b/backend/app/services/counts_candidates.rb
@@ -0,0 +1,55 @@
+# Bounded, authorised candidates at the same recorded point as the Counts query.
+class CountsCandidates
+  KEYS = ['resource', 'field', 'query', 'category', 'page', 'locale', 'at',
+          'execution_at', 'timezone'].freeze
+  LIMIT = 20
+
+  def initialize(params)
+    QueryState.validate!(params, KEYS)
+    raise ArgumentError unless params.fetch('resource') == 'posts'
+    raise ArgumentError unless ['tags', 'tags_json'].include?(params.fetch('field'))
+
+    @params = params
+    @page = Integer(params.fetch('page', '1'), 10)
+    raise ArgumentError unless @page.between?(1, 100_000)
+    raise ArgumentError if params.fetch('query', '').bytesize > 1000
+    category = params['category']
+    raise ArgumentError if category.present? && !Tag.categories.key?(category)
+  end
+
+  def call
+    options = @params.slice('locale', 'at', 'execution_at', 'timezone')
+        .merge('definition' => 'latest', 'resource' => 'tags')
+    internal = CountsPopulation.new(options)
+    external = CountsPopulation.new(options.merge('resource' => 'nico_tags',
+        'execution_at' => internal.at.iso8601(6)))
+    language = Locale.find_by!(code: @params.fetch('locale', 'ja')).language_code
+    connection = TagVersion.connection
+    path = connection.quote("$.#{ language.to_json }.name")
+    name = "COALESCE(JSON_UNQUOTE(JSON_EXTRACT(v.names, #{ path })), v.name)"
+    sources = [[internal, 'internal', name, 'v.category'],
+               [external, 'external', 'v.name', 'NULL']].map do |population, kind, title, category|
+      population.scope.except(:select).select(Arel.sql(
+          "CONCAT('#{ kind }:', v.tag_id) AS value, v.tag_id AS id, " +
+          "#{ title } AS name, #{ category } AS category, '#{ kind }' AS kind")).to_sql
+    end
+    clauses = []
+    binds = []
+    if @params['query'].present?
+      clauses << '(name LIKE ? OR CAST(id AS CHAR) = ?)'
+      binds += ["%#{ ApplicationRecord.sanitize_sql_like(@params['query']) }%", @params['query']]
+    end
+    if @params['category'].present?
+      clauses << 'category = ?'
+      binds << @params['category']
+    end
+    where = clauses.empty? ? '' : "WHERE #{ clauses.join(' AND ') }"
+    sql = <<~SQL
+      SELECT /*+ MAX_EXECUTION_TIME(10000) */ * FROM (#{ sources.join(' UNION ALL ') }) choices
+      #{ where } ORDER BY kind, id LIMIT #{ LIMIT + 1 } OFFSET #{ (@page - 1) * LIMIT }
+    SQL
+    rows = connection.select_all(ApplicationRecord.sanitize_sql_array([sql, *binds])).to_a
+    { rows: rows.first(LIMIT), page: @page, more: rows.length > LIMIT,
+      execution_at: internal.at.iso8601(6) }
+  end
+end
diff --git a/backend/app/services/counts_condition.rb b/backend/app/services/counts_condition.rb
index 7ceccc7..5d2ec5f 100644
--- a/backend/app/services/counts_condition.rb
+++ b/backend/app/services/counts_condition.rb
@@ -44,12 +44,31 @@ class CountsCondition
       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,
+    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) }]
+    result.each do |field|
+      next if field[:type] == :interval
+
+      if field[:multiple]
+        field[:operators] = field[:operators] - ['in', 'not_in'] + ['any', 'all', 'none']
+      end
+      field[:input_types] = ['single', 'multiple']
+      if ['category', 'tag_category'].include?(field[:key].split('.').last)
+        field[:candidate_source] = 'categories'
+        field[:choices] = Tag.categories.keys.map { |value|
+          { value:, label: "common:categories.#{ value }" }
+        }
+      elsif definition.resource == 'posts' && ['tags', 'tags_json'].include?(field[:key])
+        field[:candidate_source] = 'tags'
+        field[:set_type] = 'tag_reference'
+      end
+      field[:input_types] << 'list' if field[:candidate_source]
+    end
+    result
   end
 
   def initialize(population)
@@ -61,11 +80,17 @@ class CountsCondition
 
   def apply(scope, entry)
     raise ArgumentError unless entry.is_a?(Hash)
-    raise ArgumentError if (entry.keys - ['field', 'operator', 'value', 'end', 'blank']).any?
+    allowed = ['field', 'operator', 'value', 'end', 'blank', 'input', 'values']
+    raise ArgumentError if (entry.keys - allowed).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'])
+    input = entry.fetch('input', 'single')
+    raise ArgumentError unless ['single', 'multiple', 'list'].include?(input)
+    if input == 'list' && !field[:candidate_source]
+      raise ArgumentError
+    end
     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] != ''
@@ -84,6 +109,10 @@ class CountsCondition
             end
       return scope.where(Arel.sql(sql))
     end
+    if ['in', 'not_in', 'any', 'all', 'none'].include?(entry['operator'])
+      return set_condition(scope, entry, field)
+    end
+    raise ArgumentError if entry.key?('values') || input != 'single'
     return scope if values.all? { _1.nil? || _1 == '' }
 
     parsed = values.map { parse(_1, type) }
@@ -122,6 +151,58 @@ class CountsCondition
 
   private
 
+  def set_condition(scope, entry, field)
+    return scope unless entry.key?('values')
+
+    values = entry['values']
+    raise ArgumentError unless values.is_a?(Array) && values.length <= 100
+    raise ArgumentError if [entry['value'], entry['end']].any? { !_1.nil? && _1 != '' }
+
+    parsed = values.map do |value|
+      unless (value.is_a?(String) || value.is_a?(Numeric) || [true, false].include?(value))
+        raise ArgumentError
+      end
+      raise ArgumentError if value.to_s.bytesize > 8192
+
+      if field[:set_type] == 'tag_reference'
+        raise ArgumentError unless value.is_a?(String) &&
+            value.match?(/\A(?:internal|external):[1-9][0-9]{0,17}\z/)
+        value
+      else
+        raise ArgumentError if value == '' && ![:string, :enum].include?(field[:type])
+        result = value == '' ? '' : parse(value.to_s, field[:type])
+        validate_enum!(field[:key], result) if field[:type] == :enum
+        result
+      end
+    end
+    raise ArgumentError unless parsed.uniq == parsed
+
+    operator = entry['operator']
+    if parsed.empty?
+      return ['in', 'any'].include?(operator) ? scope.none : scope
+    end
+    source, expression = source_for(field[:key])
+    if field[:set_type] == 'tag_reference'
+      source = post_tag_source
+      id = "COALESCE(#{ scalar('tag_snapshot.item', 'tag_id', :integer) }, " +
+          "#{ scalar('tag_snapshot.item', 'external_tag_id', :integer) })"
+      expression = "CONCAT(CASE WHEN #{ scalar('tag_snapshot.item', 'tag_id') } IS NULL " +
+          "THEN 'external:' ELSE 'internal:' END, #{ id })"
+    end
+    predicates = parsed.map do |_value|
+      clause = "#{ expression } = ?"
+      clause = "EXISTS (SELECT 1 FROM #{ source } WHERE #{ clause })" if source
+      clause
+    end
+    conjunction = operator == 'all' ? ' AND ' : ' OR '
+    predicate = "(#{ predicates.join(conjunction) })"
+    if ['not_in', 'none'].include?(operator)
+      predicate = source ? "NOT #{ predicate }" :
+          "(NOT #{ predicate } OR #{ blank_sql(expression, field[:type]) })"
+    end
+    scope.where(predicate, *parsed)
+  end
+
   def parse(value, type)
     return nil if value.nil? || value == ''
 
diff --git a/backend/app/services/counts_pivot_layout.rb b/backend/app/services/counts_pivot_layout.rb
index 6b38f6a..e523a34 100644
--- a/backend/app/services/counts_pivot_layout.rb
+++ b/backend/app/services/counts_pivot_layout.rb
@@ -10,7 +10,21 @@ class CountsPivotLayout
     (1...keys.length).select { order.first(_1).sort == keys.first(_1).sort }
   end
 
-  def self.headers(values, depths, next_values: nil, grand: false)
+  def self.label_key(row_count, column_count, row_depth, column_depth)
+    total = row_count + column_count
+    collapsed = total - row_depth - column_depth
+    return nil if collapsed.zero?
+    return 'grandTotal' if total >= 3 && collapsed == total
+    if (collapsed == 1 &&
+        ((row_count > 1 && row_depth < row_count) ||
+         (column_count > 1 && column_depth < column_count)))
+      return 'subtotal'
+    end
+    'singleTotal'
+  end
+
+  def self.headers(values, depths, next_values: nil, grand: false, axis_count: nil,
+                   other_count: 0, direction: :row)
     result = []
     values.each_with_index do |tuple, index|
       result << { values: tuple, kind: 'data' }
@@ -23,6 +37,15 @@ class CountsPivotLayout
       end
     end
     result << { values: [], kind: 'grand_total' } if grand
+    count = axis_count || values.first&.length || 0
+    result.each do |header|
+      depth = header[:values].length
+      label = if header[:kind] != 'data'
+                direction == :row ? label_key(count, other_count, depth, other_count) :
+                    label_key(other_count, count, other_count, depth)
+              end
+      header.merge!(depth:, axis_count: count, label_key: label)
+    end
     result
   end
 end
diff --git a/backend/app/services/counts_pivot_totals.rb b/backend/app/services/counts_pivot_totals.rb
index d7aa15c..7986d31 100644
--- a/backend/app/services/counts_pivot_totals.rb
+++ b/backend/app/services/counts_pivot_totals.rb
@@ -53,6 +53,9 @@ class CountsPivotTotals
       column_depth = record['column_depth'].to_i
       { row: (0...row_depth).map { record["v#{ _1 }"] },
         column: (0...column_depth).map { record["v#{ row_depth + _1 }"] },
+        row_depth:, column_depth:,
+        label_key: CountsPivotLayout.label_key(@axes.rows.length, @axes.columns.length,
+            row_depth, column_depth),
         count: record['count'].to_i }
     end
   end
diff --git a/backend/app/services/counts_population.rb b/backend/app/services/counts_population.rb
index bc77147..c3d8fb4 100644
--- a/backend/app/services/counts_population.rb
+++ b/backend/app/services/counts_population.rb
@@ -103,7 +103,21 @@ class CountsPopulation
     conditions = QueryState.records(params, 'conditions')
     raise ArgumentError unless conditions.is_a?(Array) && conditions.length <= 100
 
-    conditions.each { apply_condition(_1) }
+    values = QueryState.records(params, 'condition_values')
+    values.each do |entry|
+      index = entry.fetch('condition')
+      raise ArgumentError unless index.between?(0, conditions.length - 1)
+      raise ArgumentError unless conditions[index]['values'] == true
+    end
+    conditions.each_with_index do |entry, index|
+      if entry.key?('values')
+        raise ArgumentError unless entry['values'] == true
+
+        entry = entry.merge('values' => values.select { _1['condition'] == index }
+            .map { _1.fetch('value') })
+      end
+      apply_condition(entry)
+    end
     drills = QueryState.records(params, 'drill')
     raise ArgumentError unless drills.is_a?(Array) && drills.length <= 100
 
diff --git a/backend/app/services/counts_resource_definition.rb b/backend/app/services/counts_resource_definition.rb
index 50e9131..cbe7f0b 100644
--- a/backend/app/services/counts_resource_definition.rb
+++ b/backend/app/services/counts_resource_definition.rb
@@ -46,9 +46,10 @@ class CountsResourceDefinition
           'source_kind' => :enum, 'source_uri' => :string, 'source_path' => :string,
           'source_file_id' => :string, 'normalized_source_key' => :string }] }.freeze
   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'],
+      string: ['eq', 'ne', 'like', 'in', 'not_in'],
+      enum: ['eq', 'ne', 'in', 'not_in'], boolean: ['eq', 'ne', 'in', 'not_in'],
+      integer: ['eq', 'ne', 'gt', 'lt', 'ge', 'le', 'range', 'in', 'not_in'],
+      datetime: ['eq', 'ne', 'gt', 'lt', 'ge', 'le', 'range', 'in', 'not_in'],
       interval: ['range'] }.freeze
   LABELS = {
       'resource_id' => 'counts:columns.resourceId', 'version_no' => 'counts:columns.version',
diff --git a/backend/app/services/counts_table_export.rb b/backend/app/services/counts_table_export.rb
index b9dd438..16bdbe7 100644
--- a/backend/app/services/counts_table_export.rb
+++ b/backend/app/services/counts_table_export.rb
@@ -143,8 +143,8 @@ class CountsTableExport
   end
 
   def total_label(header)
-    key = header[:kind] == 'grand_total' ?
-        (@query.axes.all.length == 1 ? 'singleTotal' : 'grandTotal') : 'subtotal'
+    key = header[:label_key] || (header[:kind] == 'grand_total' ?
+        (@query.axes.all.length == 1 ? 'singleTotal' : 'grandTotal') : 'subtotal')
     @labels.fetch(key, '')
   end
 
@@ -152,9 +152,10 @@ class CountsTableExport
     values = header[:values].each_with_index.map { |value, index|
       summary_value(value, index, page)
     }
-    if header[:kind] == 'data' && @previous_pivot_row&.fetch(:kind) == 'data'
+    if @previous_pivot_row
       values.each_index do |index|
-        if header[:values].first(index + 1) == @previous_pivot_row[:values].first(index + 1)
+        if (@previous_pivot_row[:values].length > index &&
+            header[:values].first(index + 1) == @previous_pivot_row[:values].first(index + 1))
           values[index] = ''
         end
       end
@@ -234,6 +235,8 @@ class CountsTableExport
     { row: row[:values], column: column[:values], kind:,
       row_kind: row[:kind], column_kind: column[:kind],
       row_depth: row[:values].length, column_depth: column[:values].length,
+      label_key: CountsPivotLayout.label_key(@query.axes.rows.length, @query.axes.columns.length,
+          row[:values].length, column[:values].length),
       count: @pivot_lookup.fetch([row[:values], column[:values]], 0) }
   end
 
diff --git a/backend/app/services/counts_table_query.rb b/backend/app/services/counts_table_query.rb
index 99aeeca..6895572 100644
--- a/backend/app/services/counts_table_query.rb
+++ b/backend/app/services/counts_table_query.rb
@@ -5,7 +5,8 @@ class CountsTableQuery
 
   KEYS = ['resource', 'definition', 'mode', 'at', 'execution_at', 'from', 'through',
           'timezone', 'rows', 'cols', 'conditions', 'drill', 'tags', 'tag_refs', 'match',
-          'tag', 'kind', 'resource_id', 'user_id', 'page', 'limit', 'sort', 'locale', 'measures', 'column_order'].freeze
+          'tag', 'kind', 'resource_id', 'user_id', 'page', 'limit', 'sort', 'locale',
+          'measures', 'column_order', 'condition_values'].freeze
   attr_reader :population, :axes, :page, :limit, :mode
 
   def initialize(params)
@@ -145,14 +146,19 @@ class CountsTableQuery
     end
     column_depths = CountsPivotLayout.depths(column_keys, column_sort, measures: false)
     row_headers = CountsPivotLayout.headers(row_values, row_depths,
-        next_values: next_row && row_keys.map { next_row[_1] }, grand: axes.rows.any?)
+        next_values: next_row && row_keys.map { next_row[_1] }, grand: axes.rows.any?,
+        axis_count: axes.rows.length, other_count: axes.columns.length)
     if axes.rows.empty? && axes.columns.any?
-      row_headers = [{ values: [], kind: 'grand_total' }]
+      row_headers = CountsPivotLayout.headers([[]], [], axis_count: 0,
+          other_count: axes.columns.length).map { _1.merge(kind: 'grand_total') }
     end
     column_headers = CountsPivotLayout.headers(column_values, column_depths,
-        grand: axes.columns.any?)
+        grand: axes.columns.any?, axis_count: axes.columns.length,
+        other_count: axes.rows.length, direction: :column)
     if axes.columns.empty? && axes.rows.any?
-      column_headers = [{ values: [], kind: 'grand_total' }]
+      column_headers = CountsPivotLayout.headers([[]], [], axis_count: 0,
+          other_count: axes.rows.length, direction: :column)
+          .map { _1.merge(kind: 'grand_total') }
     end
     totals = CountsPivotTotals.new(population, axes, row_headers, column_headers).call
     { group_count: total,
diff --git a/backend/app/services/query_state.rb b/backend/app/services/query_state.rb
index 37c9db4..5002e30 100644
--- a/backend/app/services/query_state.rb
+++ b/backend/app/services/query_state.rb
@@ -1,7 +1,8 @@
 # Public query grammar shared with frontend/src/lib/queryState.ts.
 class QueryState
   SCHEMAS = {
-      'conditions' => ['field', 'operator', 'value', 'end', 'blank'],
+      'conditions' => ['field', 'operator', 'value', 'end', 'blank', 'input', 'values'],
+      'condition_values' => ['condition', 'value', 'value_type'],
       'drill' => ['field', 'grain', 'value', 'value_type'],
       'tag_refs' => ['name', 'tag_id', 'external_tag_id', 'negative', 'missing'],
       'column_order' => ['value', 'value_type'],
@@ -40,11 +41,11 @@ class QueryState
 
       _root, index, field = name.split('.')
       record = records[index.to_i] ||= {}
-      if ['blank', 'negative', 'missing'].include?(field)
+      if ['blank', 'negative', 'missing', 'values'].include?(field)
         raise ArgumentError unless ['0', '1'].include?(value)
 
         value = value == '1'
-      elsif ['tag_id', 'external_tag_id', 'axis'].include?(field)
+      elsif ['tag_id', 'external_tag_id', 'axis', 'condition'].include?(field)
         raise ArgumentError unless value.match?(/\A[0-9]{1,18}\z/)
 
         value = value.to_i
@@ -56,7 +57,7 @@ class QueryState
 
     records.sort.map do |_index, record|
       type = record.delete('value_type')
-      if ['drill', 'measures', 'column_order'].include?(key)
+      if ['drill', 'measures', 'column_order', 'condition_values'].include?(key)
         raise ArgumentError unless ['null', 'string', 'number', 'boolean'].include?(type)
 
         raise ArgumentError unless type == 'null' || record.key?('value')
diff --git a/backend/config/routes.rb b/backend/config/routes.rb
index faecb5c..c99dc7a 100644
--- a/backend/config/routes.rb
+++ b/backend/config/routes.rb
@@ -1,5 +1,6 @@
 Rails.application.routes.draw do
   get 'counts/definitions/:resource', to: 'counts_tables#definition'
+  get 'counts/definitions/:resource/candidates', to: 'counts_tables#candidates'
   get 'counts/query', to: 'counts_tables#index'
   post 'counts/export/jobs', to: 'counts_exports#create_job'
   get 'counts/export/jobs/:token', to: 'counts_exports#job_status'
diff --git a/frontend/server.mjs b/frontend/server.mjs
index 9dfcc76..0e4a1e5 100644
--- a/frontend/server.mjs
+++ b/frontend/server.mjs
@@ -5,7 +5,7 @@ import { request as requestHTTPS } from 'node:https'
 import path from 'node:path'
 import { fileURLToPath } from 'node:url'
 
-import { render, renderSitemap } from './dist/server/entry-server.js'
+import { isCountsPath, render, renderSitemap } from './dist/server/entry-server.js'
 
 const root = fileURLToPath (new URL ('./dist/client/', import.meta.url))
 const template = await readFile (path.join (root, 'index.html'), 'utf8')
@@ -61,6 +61,8 @@ const server = createServer (async (request, response) => {
   {
     const url = new URL (request.url, origin)
     const pathname = decodeURIComponent (url.pathname)
+    const countsPage = isCountsPath (pathname)
+    if (countsPage) response.setHeader ('X-Robots-Tag', 'noindex')
     if (pathname === '/sitemap.xml' || pathname.startsWith ('/sitemap-'))
     {
       const result = await renderSitemap (url.pathname, origin, apiBaseURL)
@@ -108,7 +110,7 @@ const server = createServer (async (request, response) => {
       return
     }
     const html = result?.html == null
-        ? template.replace ('<!-- helmet -->', result?.status === 404
+        ? template.replace ('<!-- helmet -->', (result?.status === 404 || countsPage)
             ? '<meta name="robots" content="noindex" data-rh="true">' : '')
         : template
 	.replace ('lang="ja"', `lang="${result.locale}"`)
diff --git a/frontend/src/App.tsx b/frontend/src/App.tsx
index 2fc3e97..3feb7d9 100644
--- a/frontend/src/App.tsx
+++ b/frontend/src/App.tsx
@@ -23,6 +23,7 @@ import { prepareHelpPage } from '@/lib/help'
 import { fetchLocales, isLocaleCode, legacyLocalePath,
 	 switchLocalePath, unlocalisedPath } from '@/lib/locales'
 import { isAuthorityDependentQuery, localesKeys, sessionKeys } from '@/lib/queryKeys'
+import { isCountsPath } from '@/lib/routeLocales'
 import { switchPostFilterLocale } from '@/lib/posts'
 import { switchWikiLocale } from '@/lib/wiki'
 import { useLocale } from '@/lib/useLocale'
@@ -199,19 +200,19 @@ export const pageRoutes = (
       handle: { locale: 'ja', sitemap: ['static'], preload: locale => locale === 'ja'
 	  ? GekanatorPage.preload () : GekanatorUnavailablePage.preload () } },
     { path: 'counts', element: <CountsResourcePage resource="posts"/>,
-      handle: { preload: CountsResourcePage.preload } },
+      handle: { preload: CountsResourcePage.preload, prefetch: false, robots: 'noindex' } },
     { path: 'counts/posts', element: <CountsResourcePage resource="posts"/>,
-      handle: { preload: CountsResourcePage.preload } },
+      handle: { preload: CountsResourcePage.preload, prefetch: false, robots: 'noindex' } },
     { path: 'counts/tags', element: <CountsResourcePage resource="tags"/>,
-      handle: { preload: CountsResourcePage.preload } },
+      handle: { preload: CountsResourcePage.preload, prefetch: false, robots: 'noindex' } },
     { path: 'counts/nico_tags', element: <CountsResourcePage resource="nico_tags"/>,
-      handle: { preload: CountsResourcePage.preload } },
+      handle: { preload: CountsResourcePage.preload, prefetch: false, robots: 'noindex' } },
     { path: 'counts/tag_descriptions', element: <CountsResourcePage resource="tag_descriptions"/>,
-      handle: { preload: CountsResourcePage.preload } },
+      handle: { preload: CountsResourcePage.preload, prefetch: false, robots: 'noindex' } },
     { path: 'counts/tag_groups', element: <CountsResourcePage resource="tag_groups"/>,
-      handle: { preload: CountsResourcePage.preload } },
+      handle: { preload: CountsResourcePage.preload, prefetch: false, robots: 'noindex' } },
     { path: 'counts/materials', element: <CountsResourcePage resource="materials"/>,
-      handle: { preload: CountsResourcePage.preload } },
+      handle: { preload: CountsResourcePage.preload, prefetch: false, robots: 'noindex' } },
     { path: 'more', element: <MorePage/>,
       handle: { preload: MorePage.preload, sitemap: ['static'] } },
     { path: '*', element: <NotFound/>, handle: { notFound: true } }]
@@ -224,8 +225,11 @@ const matchPageRoutes = (pathname: string) =>
 export const preloadPageRoute = async (
     pathname: string,
     locale: LocaleCode,
+    intent: 'navigation' | 'prefetch' = 'navigation',
 ): Promise<void> => {
+  if (intent === 'prefetch' && isCountsPath (pathname)) return
   await Promise.all ((matchPageRoutes (pathname) ?? [])
+      .filter (match => intent === 'navigation' || match.route.handle?.prefetch !== false)
       .map (match => match.route.handle?.preload?.(locale)))
 }
 
@@ -262,7 +266,7 @@ const RoutedApp = ({ locales }: { locales: AvailableLocale[] }) => {
   const location = useLocation ()
   const locale = useLocale ()
   const route = resolvePageRoute (location.pathname)
-  const robots = route?.route.handle?.robots
+  const robots = isCountsPath (location.pathname) ? 'noindex' : route?.route.handle?.robots
   const pagePath = unlocalisedPath (location.pathname)
   const countsPage = pagePath === '/counts' || pagePath.startsWith ('/counts/')
   const switchLocale = async (targetLocale: LocaleCode): Promise<string> => {
diff --git a/frontend/src/components/PrefetchLink.tsx b/frontend/src/components/PrefetchLink.tsx
index 01a4c01..27aefc7 100644
--- a/frontend/src/components/PrefetchLink.tsx
+++ b/frontend/src/components/PrefetchLink.tsx
@@ -7,6 +7,7 @@ import { localiseTo } from '@/lib/locales'
 import { useLocale, useLocaleNavigate } from '@/lib/useLocale'
 import { useOverlayStore } from '@/components/RouteBlockerOverlay'
 import { prefetchForURL } from '@/lib/prefetchers'
+import { isCountsPath } from '@/lib/routeLocales'
 import { useClientBehaviourSettings } from '@/lib/useClientBehaviourSettings'
 import { cn } from '@/lib/utils'
 import { currentRenderContext } from '@/lib/renderContext'
@@ -53,6 +54,7 @@ export default forwardRef<HTMLAnchorElement, Props> (({
   const setOverlay = useOverlayStore (s => s.setActive)
 
   const doPrefetch = async () => {
+    if (isCountsPath (new URL (url).pathname)) return true
     try
     {
       await prefetchForURL (qc, url)
@@ -94,6 +96,12 @@ export default forwardRef<HTMLAnchorElement, Props> (({
 
       ev.preventDefault ()
 
+      if (isCountsPath (new URL (url).pathname))
+      {
+	navigate (path, { replace, ...(state && { state }) })
+	return
+      }
+
       flushSync (() => {
 	setOverlay (true)
       })
diff --git a/frontend/src/components/counts/CountsAdditionalConditions.tsx b/frontend/src/components/counts/CountsAdditionalConditions.tsx
index 27cc5b5..b7ab3b5 100644
--- a/frontend/src/components/counts/CountsAdditionalConditions.tsx
+++ b/frontend/src/components/counts/CountsAdditionalConditions.tsx
@@ -1,9 +1,10 @@
 import { useEffect, useState } from 'react'
 
+import CountsConditionValues from '@/components/counts/CountsConditionValues'
 import DateTimeField from '@/components/common/DateTimeField'
 import { Button } from '@/components/ui/button'
-import { countsEventTypes, countsFieldLabel, countsFilterFields,
-	 useCountsDefinition }
+import { countsConditionInputs, countsEventTypes, countsFieldLabel, countsFilterFields,
+	 countsSetOperators, useCountsDefinition }
     from '@/lib/countsDefinitions'
 import useDialogue from '@/lib/dialogues/useDialogue'
 import { inputClass } from '@/lib/utils'
@@ -33,12 +34,14 @@ const ConditionEditor = (
   })
   const { field, operator } = condition
   const operators = fields.find (item => item.key === field)?.operators ?? []
+  const inputs = countsConditionInputs (fields.find (item => item.key === field), operator)
   useEffect (() => {
     controls.setActions ([{ label: label (initial == null ? 'add' : 'shared:actions.edit'),
 	onSelect: () => save (condition) }])
   }, [controls, condition, initial, label, save])
   return <div className="space-y-2">
-    <select value={field} aria-label={message ('field').text} className={inputClass ()}
+    <select value={field} aria-label={message ('field').text}
+	className={inputClass (false, 'h-9 w-full')}
 	onChange={event => {
 	  const field = event.target.value
 	  const operator = fields.find (item => item.key === field)?.operators[0]
@@ -47,17 +50,39 @@ const ConditionEditor = (
       {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 ()}
+    <select value={operator} aria-label={message ('operator').text}
+	className={inputClass (false, 'h-9 w-full')}
 	onChange={event => setCondition (previous => {
 	  const operator = event.target.value
 	  const next = { ...previous, operator }
 	  if (operator !== 'range') delete next.end
 	  if ((operator === 'like') !== (previous.operator === 'like')) delete next.value
+	  const choices = countsConditionInputs (fields.find (item => item.key === field), operator)
+	  if (countsSetOperators.includes (operator))
+	  {
+	    delete next.value
+	    delete next.end
+	    next.input = choices.includes (previous.input ?? 'single') ? previous.input : choices[0]
+	  }
+	  else
+	  {
+	    delete next.values
+	    delete next.input
+	  }
 	  return next
 	})}>
       {operators.map (key => <option key={key} value={key}>
         {message (`operators.${key}`).text}</option>)}
     </select>
+    <label className="block text-sm">{label ('pattern.input')}
+      <select value={condition.input ?? inputs[0]}
+	  className={inputClass (false, 'h-9 w-full')}
+	  onChange={event => setCondition (previous => ({ ...previous,
+	      input: event.target.value as CountsCondition['input'] }))}>
+	{inputs.map (input => <option key={input} value={input}>
+	  {message (`pattern.${input}`).text}</option>)}
+      </select>
+    </label>
   </div>
 }
 
@@ -99,7 +124,7 @@ const CountsAdditionalConditions = ({ params, update }: {
       const options: string[] = type === 'boolean' ? ['true', 'false'] : [...countsEventTypes]
       const namespace = type === 'boolean' ? 'truthValues' : 'events'
       return <select value={condition[key] ?? ''} disabled={condition.blank}
-	  className={inputClass (false, 'h-7 w-36 min-w-0 max-w-full py-1')}
+	  className={inputClass (false, 'h-9 w-36 min-w-0 max-w-full py-1')}
 	  aria-label={aria.text}
 	  lang={aria.language}
 	  onChange={event => patch (index, { [key]: event.target.value })}>
@@ -110,13 +135,13 @@ const CountsAdditionalConditions = ({ params, update }: {
       </select>
     }
     if (type === 'datetime')
-      return <DateTimeField precision="second" className="h-7 w-48 min-w-0 max-w-full py-1"
+      return <DateTimeField precision="second" className="h-9 w-48 min-w-0 max-w-full py-1"
 	  value={condition[key] ?? ''} disabled={condition.blank}
 	  aria-label={aria.text} lang={aria.language}
 	  onChange={value => patch (index, { [key]: value ?? '' })}/>
     return <input value={condition[key] ?? ''} disabled={condition.blank}
 	type={(type === 'integer' || type === 'interval') ? 'number' : 'text'}
-	className={inputClass (false, 'h-7 w-36 min-w-0 max-w-full py-1')}
+	className={inputClass (false, 'h-9 w-36 min-w-0 max-w-full py-1')}
 	aria-label={aria.text} lang={aria.language}
 	onChange={event => patch (index, { [key]: event.target.value })}/>
   }
@@ -130,24 +155,32 @@ const CountsAdditionalConditions = ({ params, update }: {
 	  <Button type="button" variant="ghost" size="sm" onClick={() => edit (index)}
 	      aria-label={`${fieldName (condition.field)} ${message (
 		  `operators.${condition.operator}`).text}`}
-	      className="h-7 min-w-0 max-w-full justify-start gap-2 whitespace-normal px-1 text-left">
+	      className="min-w-0 max-w-full justify-start gap-2 whitespace-normal px-1 text-left">
 	    <span className="min-w-0 break-words">{fieldName (condition.field)}</span>
 	    {condition.operator !== 'range' && <span aria-hidden="true" className="shrink-0">
 	      {label (`operatorSymbols.${condition.operator}`)}</span>}
 	  </Button>
+	  {countsSetOperators.includes (condition.operator) ? (
+	      <CountsConditionValues key={`${condition.field}:${condition.operator}`}
+		  condition={condition}
+		  field={metadata.find (field => field.key === condition.field)!}
+		  definition={definition} params={params}
+		  maximum={Math.max (0, 100 - conditions.reduce ((sum, item, position) =>
+		      sum + (position === index ? 0 : item.values?.length ?? 0), 0))}
+		  change={values => patch (index, { values })}/>) : (
 	  <div className="inline-flex min-w-0 max-w-full items-center gap-1">
 	    {valueInput (condition, index, 'value')}
 	    {condition.operator === 'range' && <>
 	      <span aria-hidden="true" className="shrink-0">{label ('operatorSymbols.range')}</span>
 	      {valueInput (condition, index, 'end')}
 	    </>}
-	  </div>
+	  </div>)}
 	  <div className="inline-flex shrink-0 items-center gap-1">
 	    <label className="inline-flex items-center gap-1 text-sm">
 	      <input type="checkbox" checked={condition.blank ?? false}
 		  onChange={event => patch (index, { blank: event.target.checked })}/>
 	      {label ('blank')}</label>
-	    <Button type="button" variant="ghost" size="sm" className="h-7 px-1"
+	    <Button type="button" variant="ghost" size="sm" className="px-1"
 		aria-label={message ('remove').text}
 		onClick={() => write (conditions.filter ((_, position) => index !== position))}>
 	      ×</Button>
diff --git a/frontend/src/components/counts/CountsCandidatePicker.tsx b/frontend/src/components/counts/CountsCandidatePicker.tsx
new file mode 100644
index 0000000..96853a2
--- /dev/null
+++ b/frontend/src/components/counts/CountsCandidatePicker.tsx
@@ -0,0 +1,139 @@
+import { useQuery } from '@tanstack/react-query'
+import { useEffect, useRef, useState } from 'react'
+
+import { Button } from '@/components/ui/button'
+import { countsUseLatest } from '@/lib/counts'
+import { fetchCountsCandidates } from '@/lib/countsDefinitions'
+import { countsKeys } from '@/lib/queryKeys'
+import { useLocale } from '@/lib/useLocale'
+import { useUITranslation } from '@/lib/useUITranslation'
+import { inputClass } from '@/lib/utils'
+
+import type { DialogueFormControls } from '@/lib/dialogues/useDialogue'
+import type { CountsCandidate, CountsDefinition, CountsFieldMetadata }
+    from '@/lib/countsDefinitions'
+
+
+const CountsCandidatePicker = (
+    { field, definition, params, initial, maximum, controls, save }: {
+	field: CountsFieldMetadata; params: URLSearchParams
+	definition: CountsDefinition
+	initial: (string | number | boolean)[]; maximum: number
+	controls: DialogueFormControls; save: (values: string[]) => void },
+) => {
+  const { label, message } = useUITranslation ('counts')
+  const locale = useLocale ()
+  const [selected, setSelected] = useState (() => new Set (initial.map (String)))
+  const [columns, setColumns] = useState (['id', 'name', 'category', 'kind'])
+  const [draft, setDraft] = useState ('')
+  const [search, setSearch] = useState ('')
+  const [category, setCategory] = useState ('')
+  const [page, setPage] = useState (1)
+  const point = useRef (params.get ('execution_at'))
+  const request = new URLSearchParams ({ field: field.key, query: search, page: String (page) })
+  for (const key of ['timezone', 'at', 'execution_at'])
+    if (params.has (key)) request.set (key, params.get (key)!)
+  if (countsUseLatest (params)) request.delete ('at')
+  if (category) request.set ('category', category)
+  const dynamic = field.candidateSource === 'tags'
+  const { data, isFetching: fetching, isError: errorFlg } = useQuery ({
+      queryKey: countsKeys.candidates (request.toString (), locale), enabled: dynamic,
+      queryFn: ({ signal }) => {
+	const pinned = new URLSearchParams (request)
+	if (point.current != null) pinned.set ('execution_at', point.current)
+	return fetchCountsCandidates (pinned, locale, signal)
+      }, retry: false })
+  useEffect (() => {
+    if (data != null) point.current = data.executionAt
+  }, [data])
+  useEffect (() => {
+    controls.setActions ([{ label: label ('pattern.selection'),
+	onSelect: () => save ([...selected]) }])
+  }, [controls, label, save, selected])
+  const fixed: CountsCandidate[] = (field.choices ?? []).map (choice => ({
+      value: choice.value, name: message (choice.label).text }))
+  const rows = dynamic ? data?.rows ?? [] : fixed.filter (row =>
+      row.name?.includes (search))
+  const headings: Record<string, string> = {
+      id: 'columns.resourceId', name: 'columns.name', category: 'common:categoryLabel',
+      kind: 'columns.kind' }
+  const available = dynamic ? ['id', 'name', 'category', 'kind'] : ['name']
+  const visible = available.filter (column => columns.includes (column))
+  const categories = definition.filterFields?.find (field =>
+      field.candidateSource === 'categories')?.choices ?? []
+  const cell = (row: CountsCandidate, column: string) => {
+    if (column === 'category') return row.category == null ? ''
+	: message (`common:categories.${row.category}`).text
+    if (column === 'kind') return row.kind == null ? '' : message (`kinds.${row.kind}`).text
+    return column === 'id' ? row.id : row.name
+  }
+  return <div className="min-w-0 space-y-2">
+    <div className="flex min-w-0 items-center gap-2">
+      <input className={inputClass (false, 'h-9 min-w-0 flex-1')}
+	  aria-label={message ('common:search').text} value={draft}
+	  onChange={event => setDraft (event.target.value)}
+	  onKeyDown={event => {
+	    if (event.key !== 'Enter') return
+	    event.preventDefault ()
+	    setSearch (draft)
+	    setPage (1)
+	  }}/>
+      <Button type="button" onClick={() => { setSearch (draft); setPage (1) }}>
+	{label ('common:search')}</Button>
+    </div>
+    {dynamic && <select className={inputClass (false, 'h-9 w-full')}
+	aria-label={message ('common:categoryLabel').text} value={category}
+	onChange={event => { setCategory (event.target.value); setPage (1) }}>
+      <option value=""/>
+      {categories.map (choice => <option key={choice.value} value={choice.value}>
+	{message (choice.label).text}</option>)}
+    </select>}
+    <fieldset className="flex flex-wrap items-center gap-2 text-sm">
+      <legend>{label ('pattern.columns')}</legend>
+      {available.map (column => <label key={column} className="inline-flex items-center gap-1">
+	<input type="checkbox" checked={columns.includes (column)} onChange={event =>
+	    setColumns (previous => event.target.checked ? [...previous, column]
+		: previous.filter (value => value !== column))}/>{label (headings[column])}
+      </label>)}
+    </fieldset>
+    <p className="text-sm">{label ('pattern.value')}{'：'}
+      {label (dynamic ? 'columns.resourceId' : 'common:categoryLabel')}
+    </p>
+    <Button type="button" variant="ghost" size="sm" onClick={() => setSelected (new Set ())}>
+      {label ('shared:actions.reset')}</Button>
+    {errorFlg && <p role="alert">{label ('common:fetchError')}</p>}
+    <div className="max-h-[40dvh] overflow-auto" aria-busy={fetching}>
+      <table className="w-full text-left text-sm">
+	<thead><tr><th className="p-2">{label ('pattern.selection')}</th>
+	  {visible.map (column => <th key={column} className="p-2">
+	    {label (headings[column])}</th>)}
+	</tr></thead>
+	<tbody>{rows.map (row => <tr key={row.value} className="border-t dark:border-slate-700">
+	  <td className="p-2"><input type="checkbox" checked={selected.has (row.value)}
+	      aria-label={row.name ?? String (row.id ?? '')}
+	      disabled={!selected.has (row.value) && selected.size >= maximum}
+	      onChange={event => setSelected (previous => {
+		const next = new Set (previous)
+		if (event.target.checked) next.add (row.value)
+		else next.delete (row.value)
+		return next
+	      })}/></td>
+	  {visible.map (column => <td key={column} className="break-words p-2">
+	    {cell (row, column)}</td>)}
+	</tr>)}</tbody>
+      </table>
+    </div>
+    {dynamic && <div className="flex items-center justify-between gap-2">
+      <Button type="button" variant="outline" disabled={page === 1 || fetching}
+	  onClick={() => setPage (previous => previous - 1)}>
+	{label ('common:pagination.previous')}</Button>
+      <span>{page}</span>
+      <Button type="button" variant="outline" disabled={!data?.more || fetching}
+	  onClick={() => setPage (previous => previous + 1)}>
+	{label ('common:pagination.next')}</Button>
+    </div>}
+  </div>
+}
+
+
+export default CountsCandidatePicker
diff --git a/frontend/src/components/counts/CountsConditionValues.tsx b/frontend/src/components/counts/CountsConditionValues.tsx
new file mode 100644
index 0000000..e6fa713
--- /dev/null
+++ b/frontend/src/components/counts/CountsConditionValues.tsx
@@ -0,0 +1,84 @@
+import { useState } from 'react'
+
+import CountsCandidatePicker from '@/components/counts/CountsCandidatePicker'
+import DateTimeField from '@/components/common/DateTimeField'
+import { Button } from '@/components/ui/button'
+import useDialogue from '@/lib/dialogues/useDialogue'
+import { inputClass } from '@/lib/utils'
+import { useUITranslation } from '@/lib/useUITranslation'
+
+import type { CountsCondition, CountsDefinition, CountsFieldMetadata }
+    from '@/lib/countsDefinitions'
+
+
+const CountsConditionValues = (
+    { condition, field, definition, params, maximum, change }: {
+	condition: CountsCondition; field: CountsFieldMetadata; definition: CountsDefinition
+	params: URLSearchParams; maximum: number
+	change: (values: (string | number | boolean)[]) => void },
+) => {
+  const { label, message } = useUITranslation ('counts')
+  const dialogue = useDialogue ()
+  const [draft, setDraft] = useState ('')
+  const values = condition.values ?? []
+  const pick = () => {
+    void dialogue.form ({ title: label (field.candidateSource === 'tags'
+	? 'pattern.link' : 'pattern.pattern'), size: 'large', footerLayout: 'inline',
+	body: controls => <CountsCandidatePicker field={field} definition={definition}
+	    params={params} initial={values} maximum={maximum} controls={controls} save={change}/> })
+  }
+  if (condition.input === 'list' || field.candidateSource === 'tags')
+    return <Button type="button" variant="outline" disabled={condition.blank} onClick={pick}>
+      {label ('pattern.list')}{' ('}{values.length}{')'}</Button>
+  const append = () => {
+    if (draft === '' || values.length >= maximum
+	|| values.some (value => String (value) === draft))
+      return
+    change ([...values, draft])
+    setDraft ('')
+  }
+  const input = () => {
+    if (field.type === 'datetime')
+      return <DateTimeField precision="second" value={draft} disabled={condition.blank}
+	  className="h-9 w-48 min-w-0 max-w-full" aria-label={message ('value').text}
+	  onChange={value => setDraft (value ?? '')}/>
+    if (field.type === 'boolean' || field.choices != null)
+    {
+      const choices = field.choices ?? ['true', 'false'].map (value => ({
+	  value, label: `counts:truthValues.${value}` }))
+      return <select value={draft} disabled={condition.blank}
+	  className={inputClass (false, 'h-9 w-36 min-w-0 max-w-full')}
+	  aria-label={message ('value').text} onChange={event => setDraft (event.target.value)}>
+	<option value=""/>
+	{choices.map (choice => <option key={choice.value} value={choice.value}>
+	  {message (choice.label).text}</option>)}
+      </select>
+    }
+    return <input value={draft} disabled={condition.blank}
+	type={field.type === 'integer' ? 'number' : 'text'} aria-label={message ('value').text}
+	className={inputClass (false, 'h-9 w-36 min-w-0 max-w-full')}
+	onChange={event => setDraft (event.target.value)}/>
+  }
+  const display = (value: string | number | boolean) => {
+    const choice = field.choices?.find (choice => choice.value === String (value))
+    if (choice != null) return message (choice.label).text
+    if (field.type === 'boolean') return message (`truthValues.${value}`).text
+    return String (value)
+  }
+  return <div className="flex min-w-0 max-w-full flex-wrap items-center gap-1">
+    {values.map ((value, index) => <span key={`${index}:${value}`}
+	className="inline-flex items-center gap-1">
+      {display (value)}<Button type="button" size="sm" variant="ghost"
+	  aria-label={message ('remove').text} disabled={condition.blank}
+	  onClick={() => change (values.filter ((_, position) => position !== index))}>×</Button>
+    </span>)}
+    {input ()}
+    <Button type="button" variant="outline" disabled={condition.blank || draft === ''
+	|| values.length >= maximum} onClick={append}>{label ('add')}</Button>
+    <Button type="button" variant="ghost" disabled={condition.blank}
+	onClick={() => change ([])}>{label ('shared:actions.reset')}</Button>
+  </div>
+}
+
+
+export default CountsConditionValues
diff --git a/frontend/src/components/counts/CountsSummaryResults.tsx b/frontend/src/components/counts/CountsSummaryResults.tsx
index 4c4e625..37247b7 100644
--- a/frontend/src/components/counts/CountsSummaryResults.tsx
+++ b/frontend/src/components/counts/CountsSummaryResults.tsx
@@ -41,8 +41,8 @@ const CountsSummaryTable = (
   const display = (value: string | number | null, axis: CountsAxis, index: number) =>
       countsSummaryValue (value, axis, index, data, locale)
   const aggregateLabel = (header: CountsPivotHeader) => message (
-      header.kind === 'grand_total' ? (rows.length + cols.length === 1
-          ? 'singleTotal' : 'grandTotal') : 'subtotal').text
+      header.labelKey ?? (header.kind === 'grand_total' ? (rows.length + cols.length === 1
+          ? 'singleTotal' : 'grandTotal') : 'subtotal')).text
   const leading = Math.max (rows.length, cols.length > 0 ? 1 : 0)
   const levels = Math.max (1, cols.length)
   const headingLevels = cols.length === 0 ? 1 : levels * 2
@@ -77,6 +77,8 @@ const CountsSummaryTable = (
   const full = new Map (cells.map (cell => [JSON.stringify (cell.values), cell.count]))
   const totals = new Map ((data.pivotTotals ?? []).map (cell => [
       JSON.stringify ([cell.row, cell.column]), cell.count]))
+  const totalLabels = new Map ((data.pivotTotals ?? []).map (cell => [
+      JSON.stringify ([cell.row, cell.column]), cell.labelKey]))
   const count = (row: CountsPivotHeader, column: CountsPivotHeader) =>
       (row.values.length === rows.length && column.values.length === cols.length)
       ? full.get (JSON.stringify ([...row.values, ...column.values])) ?? 0
@@ -101,16 +103,16 @@ const CountsSummaryTable = (
         ...Array.from ({ length: leading }, (_, index) => labels[index] ?? '')]
   })
   const spans = rowHeaders.map ((row, index) => rows.map ((_, axis) => {
-    if (row.kind !== 'data') return 1
+    if (row.values.length <= axis) return 1
     const prefix = JSON.stringify (row.values.slice (0, axis + 1))
     const previous = rowHeaders[index - 1]
-    if (previous?.kind === 'data'
+    if (previous != null && previous.values.length > axis
         && JSON.stringify (previous.values.slice (0, axis + 1)) === prefix) return 0
     let span = 1
     while (index + span < rowHeaders.length)
     {
       const next = rowHeaders[index + span]
-      if (next.kind !== 'data'
+      if (next.values.length <= axis
           || JSON.stringify (next.values.slice (0, axis + 1)) !== prefix) break
       ++span
     }
@@ -246,8 +248,11 @@ const CountsSummaryTable = (
       <tbody>{rowHeaders.map ((row, index) => <tr key={columnKey (row)}>
         {rowLabels[index].map ((value, offset) => {
           const axis = offset - (numbered ? 1 : 0)
+          if (axis >= 0 && row.kind !== 'data' && axis > row.values.length) return null
+          const aggregate = axis >= 0 && row.kind !== 'data' && axis === row.values.length
           const span = axis < 0 ? 1 : spans[index][axis] ?? 1
           return span === 0 ? null : <td key={offset} rowSpan={span}
+              colSpan={aggregate ? leading - axis : 1}
               role={axis >= 0 ? 'rowheader' : undefined} data-counts-copy={value}
               data-counts-aggregate={row.kind !== 'data' ? '' : undefined}
               data-counts-total={row.kind !== 'data' ? row.kind : undefined}
@@ -264,7 +269,11 @@ const CountsSummaryTable = (
             data-counts-aggregate={(row.kind !== 'data' || column.kind !== 'data')
                 ? '' : undefined}
 	    className="border px-2 py-1 dark:border-slate-700">
-          <PrefetchLink to={drill (row, column)}>{count (row, column)}</PrefetchLink>
+          <PrefetchLink to={drill (row, column)} aria-label={
+              totalLabels.get (JSON.stringify ([row.values, column.values])) == null ? undefined
+              : `${message (totalLabels.get (
+                  JSON.stringify ([row.values, column.values]))!).text}: ${count (row, column)}`}>
+            {count (row, column)}</PrefetchLink>
         </td>)}
       </tr>)}</tbody>
     </CountsSelectableTable>
diff --git a/frontend/src/entry-server.tsx b/frontend/src/entry-server.tsx
index ecbb831..476e4b1 100644
--- a/frontend/src/entry-server.tsx
+++ b/frontend/src/entry-server.tsx
@@ -20,6 +20,7 @@ import type { RenderContext } from '@/lib/renderContext'
 import type { User } from '@/types'
 
 export { renderSitemap } from '@/lib/sitemap.server'
+export { isCountsPath } from '@/lib/routeLocales'
 
 type RenderedPage = {
     status: number
diff --git a/frontend/src/lib/counts.ts b/frontend/src/lib/counts.ts
index 498ab36..d863a0f 100644
--- a/frontend/src/lib/counts.ts
+++ b/frontend/src/lib/counts.ts
@@ -58,7 +58,8 @@ export type CountsStateTotals = {
     deprecatedTags: number | null
     externalAssignments: number | null }
 export type CountsPivotHeader = { values: (string | number | null)[]
-    kind: 'data' | 'subtotal' | 'grand_total' }
+    kind: 'data' | 'subtotal' | 'grand_total'
+    depth?: number; axisCount?: number; labelKey?: string | null }
 export type CountsResult = {
     populationCount?: number
     excludedCount?: number | null
@@ -70,7 +71,7 @@ export type CountsResult = {
     rowHeaders?: CountsPivotHeader[]
     columnHeaders?: CountsPivotHeader[]
     pivotTotals?: { row: (string | number | null)[]; column: (string | number | null)[]
-        count: number }[]
+        count: number; rowDepth?: number; columnDepth?: number; labelKey?: string | null }[]
     executionAt?: string
     columnValues?: (string | number | null)[][]
     cells?: { values: (string | number | null)[]; count: number }[]
diff --git a/frontend/src/lib/countsDefinitions.ts b/frontend/src/lib/countsDefinitions.ts
index a0438a0..b9b19ae 100644
--- a/frontend/src/lib/countsDefinitions.ts
+++ b/frontend/src/lib/countsDefinitions.ts
@@ -8,7 +8,8 @@ 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 }
+    field: string; operator: string; value?: string; end?: string; blank?: boolean
+    input?: 'single' | 'multiple' | 'list'; values?: (string | number | boolean)[] }
 export type CountsFieldType = 'string' | 'integer' | 'datetime' | 'enum'
     | 'json' | 'boolean' | 'interval'
 
@@ -22,7 +23,9 @@ export const visibleCountsResources = [
 
 export type CountsFieldMetadata = {
     key: string; type: CountsFieldType; nullable: boolean; operators: string[]
-    labels?: string[]; multiple?: boolean }
+    labels?: string[]; multiple?: boolean; candidateSource?: 'categories' | 'tags'
+    setType?: 'tag_reference'; inputTypes?: string[]
+    choices?: { value: string; label: string }[] }
 export type CountsDefinition = {
     fields: CountsFieldMetadata[]
     outputFields?: CountField[]
@@ -44,6 +47,31 @@ export const useCountsDefinition = (): CountsDefinition => {
 export const fetchCountsDefinition = (resource: CountsResource): Promise<CountsDefinition> =>
     apiGet (`/counts/definitions/${encodeURIComponent (resource)}`)
 
+export type CountsCandidate = {
+    value: string; id?: number; name: string | null; category?: string | null
+    kind?: 'internal' | 'external' }
+export type CountsCandidatesResult = {
+    rows: CountsCandidate[]; page: number; more: boolean; executionAt: string }
+
+export const fetchCountsCandidates = (
+    params: URLSearchParams,
+    locale: LocaleCode,
+    signal?: AbortSignal,
+): Promise<CountsCandidatesResult> => apiGet (
+    '/counts/definitions/posts/candidates', {
+	params: Object.fromEntries (params), locale, signal })
+
+export const countsSetOperators = ['in', 'not_in', 'any', 'all', 'none']
+
+export const countsConditionInputs = (
+    field: CountsFieldMetadata | undefined,
+    operator: string,
+): ('single' | 'multiple' | 'list')[] => {
+  if (!countsSetOperators.includes (operator)) return ['single']
+  if (field?.candidateSource === 'tags') return ['list']
+  return field?.candidateSource == null ? ['multiple'] : ['list', 'multiple']
+}
+
 
 export const countsFilterFields = (
     definition: CountsDefinition,
diff --git a/frontend/src/lib/prefetchers.ts b/frontend/src/lib/prefetchers.ts
index e6dc7d8..db146ac 100644
--- a/frontend/src/lib/prefetchers.ts
+++ b/frontend/src/lib/prefetchers.ts
@@ -1,5 +1,3 @@
-import { queryRecordParams } from '@/lib/queryState'
-import { QueryClient } from '@tanstack/react-query'
 import { match } from 'path-to-regexp'
 
 import { getHelpArticle,
@@ -11,12 +9,16 @@ import { getHelpArticle,
 import { localeFromPath, localeLanguage, unlocalisedPath } from '@/lib/locales'
 import { fetchPost, fetchPosts, fetchPostChanges } from '@/lib/posts'
 import { helpKeys, postsKeys, tagsKeys, wikiKeys } from '@/lib/queryKeys'
+import { queryRecordParams } from '@/lib/queryState'
+import { isCountsPath } from '@/lib/routeLocales'
 import { fetchNicoTags, fetchTag, fetchTagChanges, fetchTags } from '@/lib/tags'
 import { fetchWikiAutolinkCandidates,
 	 fetchWikiPageByReference,
 	 fetchWikiTag,
 	 fetchWikiPages } from '@/lib/wiki'
 
+import type { QueryClient } from '@tanstack/react-query'
+
 import type { LocaleCode } from '@/lib/locales'
 import type { Category, FetchPostsOrder, FetchTagsOrder, WikiTagReference } from '@/types'
 
@@ -326,6 +328,7 @@ export const routePrefetchers: { test: (u: URL) => boolean; run: Prefetcher }[]
 
 export const prefetchForURL = async (qc: QueryClient, urlLike: string): Promise<void> => {
   const u = new URL (urlLike, location.origin)
+  if (isCountsPath (u.pathname)) return
   if (u.origin !== location.origin)
     return
 
diff --git a/frontend/src/lib/queryKeys.ts b/frontend/src/lib/queryKeys.ts
index e7828fc..b570657 100644
--- a/frontend/src/lib/queryKeys.ts
+++ b/frontend/src/lib/queryKeys.ts
@@ -173,5 +173,6 @@ export const theatresKeys = {
 
 export const countsKeys = {
     definition: (resource: string) => ['counts', 'definition', resource] as const,
+    candidates: (params: string, locale: LocaleCode) => ['counts', 'candidates', locale, params] as const,
     index: (resource: string, params: string, locale: LocaleCode) =>
 	['counts', resource, locale, params] as const }
diff --git a/frontend/src/lib/queryState.ts b/frontend/src/lib/queryState.ts
index cd7c9c3..432f2e2 100644
--- a/frontend/src/lib/queryState.ts
+++ b/frontend/src/lib/queryState.ts
@@ -1,7 +1,8 @@
 // Public URL grammar: space-delimited tokens and indexed scalar fields, never JSON.
 export type QueryRecord = Record<string, string | number | boolean | null | undefined>
 const schemas: Record<string, string[]> = {
-    conditions: ['field', 'operator', 'value', 'end', 'blank'],
+    conditions: ['field', 'operator', 'value', 'end', 'blank', 'input', 'values'],
+    condition_values: ['condition', 'value', 'value_type'],
     drill: ['field', 'grain', 'value', 'value_type'],
     tag_refs: ['name', 'tag_id', 'external_tag_id', 'negative', 'missing'],
     column_order: ['value', 'value_type'],
@@ -23,8 +24,8 @@ export const queryRecords = (params: URLSearchParams, key: string): QueryRecord[
     const index = Number (parts[0])
     const record = indexed.get (index) ?? { }
     const field = parts[1]
-    record[field] = ['blank', 'negative', 'missing'].includes (field)
-        ? value === '1' : (['tag_id', 'external_tag_id', 'axis'].includes (field)
+    record[field] = ['blank', 'negative', 'missing', 'values'].includes (field)
+        ? value === '1' : (['tag_id', 'external_tag_id', 'axis', 'condition'].includes (field)
             ? Number (value) : value)
     indexed.set (index, record)
   }
@@ -52,11 +53,13 @@ export const setQueryRecords = (
       if (value == null && field !== 'value') continue
       if (!schemas[key]?.includes (field)) continue
       const name = `${key}.${index}.${field}`
-      if (field === 'value' && ['drill', 'measures', 'column_order'].includes (key))
+      if (field === 'value'
+	  && ['drill', 'measures', 'column_order', 'condition_values'].includes (key))
         params.set (`${key}.${index}.value_type`, value == null ? 'null' : typeof value)
       if (value == null) continue
       params.set (name, typeof value === 'boolean'
-          ? (['blank', 'negative', 'missing'].includes (field) ? (value ? '1' : '0') : String (value))
+          ? (['blank', 'negative', 'missing', 'values'].includes (field)
+	      ? (value ? '1' : '0') : String (value))
           : String (value))
     }
   })
@@ -74,16 +77,34 @@ export const readCountState = <T,> (
       const [field, grain] = token.split (':')
       return grain == null ? { field } : { field, grain }
     }) as T
-  return queryRecords (params, key) as T
+  const records = queryRecords (params, key)
+  if (key === 'conditions')
+  {
+    const values = queryRecords (params, 'condition_values')
+    return records.map ((record, index) => record.values === true
+	? { ...record, values: values.filter (entry => entry.condition === index)
+	    .map (entry => entry.value) } : record) as T
+  }
+  return records as T
 }
 
 
-export const encodeCountState = (key: string, records: QueryRecord[]): string => {
+export const encodeCountState = (key: string, records: Record<string, unknown>[]): string => {
   if (key === 'rows' || key === 'cols')
     return records.map (record => record.grain == null
         ? String (record.field) : `${record.field}:${record.grain}`).join (' ')
   const params = new URLSearchParams ()
-  setQueryRecords (params, key, records)
+  const values: QueryRecord[] = []
+  const flat = records.map ((record, condition) => {
+    if (key !== 'conditions' || !Array.isArray (record.values)) return record as QueryRecord
+    const { values: selected, ...fields } = record
+    for (const value of selected as unknown[])
+      values.push ({ condition, value: value as string | number | boolean })
+    return { ...fields, values: true } as QueryRecord
+  })
+  setQueryRecords (params, key, flat)
+  if (key === 'conditions' && flat.some (record => record.values === true))
+    setQueryRecords (params, 'condition_values', values)
   return params.toString ()
 }
 
@@ -93,6 +114,14 @@ export const setCountState = (params: URLSearchParams, key: string, value: strin
   {
     const fields = new URLSearchParams (value)
     setQueryRecords (params, key, queryRecords (fields, key))
+    if (key === 'conditions')
+    {
+      for (const name of [...params.keys ()])
+        if (name === 'condition_values' || name.startsWith ('condition_values.'))
+	  params.delete (name)
+      if (fields.has ('condition_values'))
+        setQueryRecords (params, 'condition_values', queryRecords (fields, 'condition_values'))
+    }
   }
   else params.set (key, value)
 }
diff --git a/frontend/src/lib/routeLocales.ts b/frontend/src/lib/routeLocales.ts
index 7c16a66..88ea678 100644
--- a/frontend/src/lib/routeLocales.ts
+++ b/frontend/src/lib/routeLocales.ts
@@ -1,3 +1,5 @@
+import { unlocalisedPath } from '@/lib/locales'
+
 import type { QueryClient } from '@tanstack/react-query'
 import type { IndexRouteObject, Location, NonIndexRouteObject, Params } from 'react-router-dom'
 
@@ -20,6 +22,7 @@ export type SitemapSource =
     | 'descriptions' | 'tag_groups' | 'theatres'
 
 export type PageRouteHandle = {
+    prefetch?: false
     preload?: (locale: LocaleCode) => Promise<unknown>
     prepare?: (request: PagePreparation) => Promise<number>
     switchLocale?: (request: LocaleSwitchRequest) => Promise<string>
@@ -33,3 +36,9 @@ export type PageRouteHandle = {
 export type PageRoute = { handle?: PageRouteHandle } & (
     Omit<IndexRouteObject, 'handle'>
     | (Omit<NonIndexRouteObject, 'handle' | 'children'> & { children?: PageRoute[] }))
+
+
+export const isCountsPath = (pathname: string): boolean => {
+  const path = unlocalisedPath (pathname).toLowerCase ()
+  return path === '/counts' || path.startsWith ('/counts/')
+}
diff --git a/frontend/src/lib/sitemap.server.ts b/frontend/src/lib/sitemap.server.ts
index e3b7a77..8b2cb54 100644
--- a/frontend/src/lib/sitemap.server.ts
+++ b/frontend/src/lib/sitemap.server.ts
@@ -5,6 +5,7 @@ import { apiGet, isApiError } from '@/lib/api'
 import { parseHelpEdition } from '@/lib/help'
 import { fetchLocales, isLocaleCode, localeLanguage } from '@/lib/locales'
 import { withRenderContext } from '@/lib/renderContext.server'
+import { isCountsPath } from '@/lib/routeLocales'
 
 import type { LocaleCode } from '@/lib/locales'
 import type { PageRoute, SitemapSource } from '@/lib/routeLocales'
@@ -27,6 +28,7 @@ const sitemapRoutes = (locale: LocaleCode): SitemapRoute[] => {
 	    || (handle?.locale != null && handle.locale !== locale))
 	  return []
 	const path = [parent, route.path].filter (Boolean).join ('/')
+	if (isCountsPath (`/${path}`)) return []
 	return [
 	    ...(handle?.sitemap ?? []).map (source => ({ path, source })),
 	    ...collect (route.children ?? [], path)]
diff --git a/frontend/src/locales/ja/counts.json b/frontend/src/locales/ja/counts.json
index c675e8b..6318aa2 100644
--- a/frontend/src/locales/ja/counts.json
+++ b/frontend/src/locales/ja/counts.json
@@ -186,6 +186,11 @@
     "hour": "時"
   },
   "operatorSymbols": {
+    "in": "IN",
+    "not_in": "NOT IN",
+    "any": "ANY",
+    "all": "ALL",
+    "none": "NONE",
     "eq": "=",
     "ne": "≠",
     "gt": ">",
@@ -196,6 +201,11 @@
     "range": "～"
   },
   "operators": {
+    "in": "IN",
+    "not_in": "NOT IN",
+    "any": "選択値のいずれかを含む",
+    "all": "選択値のすべてを含む",
+    "none": "選択値を一つも含まない",
     "eq": "等しい",
     "ne": "等しくない",
     "gt": "より大きい",
@@ -205,6 +215,17 @@
     "like": "パターン",
     "range": "範囲"
   },
+  "pattern": {
+    "input": "画面出力タイプ",
+    "single": "単一入力",
+    "multiple": "複数入力",
+    "list": "複数選択リスト",
+    "pattern": "データパターン",
+    "link": "データリンク",
+    "columns": "表示列",
+    "value": "適用値",
+    "selection": "選択"
+  },
   "events": {
     "create": "起票",
     "update": "異動",