diff --git a/backend/app/controllers/posts_controller.rb b/backend/app/controllers/posts_controller.rb
index 99da557..3843bb7 100644
--- a/backend/app/controllers/posts_controller.rb
+++ b/backend/app/controllers/posts_controller.rb
@@ -689,6 +689,7 @@ class PostsController < ApplicationController
     version.tags_json
         .select { _1.key?('tag_id') }
         .map { Post.tag_snapshot_literal(_1) }
+        .compact
         .sort
   end
 
@@ -716,7 +717,7 @@ class PostsController < ApplicationController
       next name if sections.empty?
 
       "#{ name }#{ sections.map { Post.section_literal(_1) }.join }"
-    end
+    end.compact.sort
   end
 
   def post_incoming_snapshot locale:, title:, original_created_from:, original_created_before:,
@@ -725,6 +726,7 @@ class PostsController < ApplicationController
 
     Tag.normalise_tags!(locale, tag_names,
                         with_tagme: false,
+                        with_no_deerjikist: false,
                         deny_deprecated: true,
                         with_sections: true) => { tags:, sections: }
 
diff --git a/backend/app/controllers/tag_versions_controller.rb b/backend/app/controllers/tag_versions_controller.rb
index 6709381..2aab1db 100644
--- a/backend/app/controllers/tag_versions_controller.rb
+++ b/backend/app/controllers/tag_versions_controller.rb
@@ -19,7 +19,8 @@ class TagVersionsController < ApplicationController
         SQL
       .select('tag_versions.*', 'prev.name AS prev_name', 'prev.category AS prev_category',
               'prev.deprecated_at AS prev_deprecated_at',
-              'prev.aliases AS prev_aliases', 'prev.parent_tag_ids AS prev_parent_tag_ids')
+              'prev.aliases AS prev_aliases', 'prev.names AS prev_names',
+              'prev.parent_tag_ids AS prev_parent_tag_ids')
     q = q.where('tag_versions.tag_id = ?', tag_id) if tag_id
 
     count = q.except(:select, :order, :limit, :offset).count
@@ -38,8 +39,10 @@ class TagVersionsController < ApplicationController
     users_by_id = User.where(id: user_ids).pluck(:id, :name).to_h
 
     rows.map do |row|
-      cur_aliases = split_values(row.aliases)
-      prev_aliases = split_values(row.attributes['prev_aliases'])
+      current_names = names_for_locale(row.names, language_code)
+      previous_names = names_for_locale(row.attributes['prev_names'], language_code)
+      cur_aliases = current_names.reject { _1['primary_flg'] }.map { _1['name'] }
+      prev_aliases = previous_names.reject { _1['primary_flg'] }.map { _1['name'] }
 
       cur_parent_tag_ids = split_parent_tag_ids(row.parent_tag_ids)
       prev_parent_tag_ids = split_parent_tag_ids(row.attributes['prev_parent_tag_ids'])
@@ -63,7 +66,8 @@ class TagVersionsController < ApplicationController
         version_no: row.version_no,
         event_type: row.event_type,
         names: row.names,
-        name: { current: row.name, prev: row.attributes['prev_name'] },
+        name: { current: current_names.find { _1['primary_flg'] }&.fetch('name'),
+                prev: previous_names.find { _1['primary_flg'] }&.fetch('name') },
         category: { current: row.category, prev: row.attributes['prev_category'] },
         deprecated_at: { current: row.deprecated_at&.iso8601,
                          prev: row.attributes['prev_deprecated_at']&.iso8601 },
@@ -93,5 +97,12 @@ class TagVersionsController < ApplicationController
 
   def split_values(values) = values.to_s.split(/\s+/).reject(&:blank?)
 
+  def names_for_locale names, language_code
+    values = names.is_a?(String) ? JSON.parse(names) : Array(names)
+    values.select { _1['language_code'] == language_code }
+  rescue JSON::ParserError
+    []
+  end
+
   def split_parent_tag_ids(values) = split_values(values).map(&:to_i)
 end
diff --git a/backend/app/controllers/tags_controller.rb b/backend/app/controllers/tags_controller.rb
index 53f738e..58df873 100644
--- a/backend/app/controllers/tags_controller.rb
+++ b/backend/app/controllers/tags_controller.rb
@@ -473,7 +473,7 @@ class TagsController < ApplicationController
       end
       rename_tag_name!(locale, tag, name) if name_changed
 
-      alias_names << old_name if name_changed
+      alias_names << old_name if name_changed && old_name.present?
       alias_names.delete(name)
 
       update_aliases!(locale, tag, alias_names)
@@ -772,6 +772,7 @@ class TagsController < ApplicationController
             script_code: locale.script_code,
             name:,
             primary_flg: true)
+        tag.association(:tag_names).reset
       end
       return
     end
@@ -786,6 +787,9 @@ class TagsController < ApplicationController
       TagVersioning.ensure_snapshot!(old_owner_tag, created_by_user: current_user)
     end
 
+    current_tag_name.wiki_page&.update!(tag_name_id: promoted_tag_name.id)
+    current_tag_name.association(:wiki_page).reset
+
     current_tag_name.update!(canonical_id: promoted_tag_name.id, primary_flg: false)
     promoted_tag_name.update!(tag:, canonical_id: nil, primary_flg: true)
 
@@ -797,7 +801,6 @@ class TagsController < ApplicationController
       alias_tag_name.update!(canonical_id: promoted_tag_name.id, primary_flg: false)
     end
 
-    current_tag_name.wiki_page&.update!(tag_name_id: promoted_tag_name.id)
     tag.update!(tag_name_id: promoted_tag_name.id)
     current_tag_name.association(:wiki_page).reset
     current_tag_name.association(:tag).reset
@@ -815,7 +818,9 @@ class TagsController < ApplicationController
 
     affected_tags = [tag]
 
-    primary_tag_name = tag.tag_name(locale.language_code)
+    primary_tag_name = TagName.find_by!(tag:,
+                                        language_code: locale.language_code,
+                                        primary_flg: true)
     current_aliases = tag.tag_names.where(language_code: locale.language_code,
                                           primary_flg: false).to_a
 
diff --git a/backend/app/controllers/wiki_pages_controller.rb b/backend/app/controllers/wiki_pages_controller.rb
index 9b38b0e..b0d0b8c 100644
--- a/backend/app/controllers/wiki_pages_controller.rb
+++ b/backend/app/controllers/wiki_pages_controller.rb
@@ -94,7 +94,11 @@ class WikiPagesController < ApplicationController
     return render_unprocessable_entity('タイトルは必須です．', field: :title) if title.blank?
     return render_unprocessable_entity('本文は必須です．', field: :body) if body.blank?
 
-    tag_name = TagName.find_or_create_by!(name: title)
+    tag_name = TagName.find_or_create_by!(language_code: 'ja', name: title) do |name|
+      name.script_code = 'Jpan'
+      name.primary_flg = true
+      name.auto_generated = false
+    end
 
     page =
         Wiki::Commit.create_content!(
diff --git a/backend/app/models/tag.rb b/backend/app/models/tag.rb
index e449781..fa659ee 100644
--- a/backend/app/models/tag.rb
+++ b/backend/app/models/tag.rb
@@ -64,6 +64,7 @@ class Tag < ApplicationRecord
   validates :category, presence: true, inclusion: { in: Tag.categories.keys }
 
   validate :category_must_be_deerjikist_with_deerjikists
+  validate :tag_names_must_be_valid
 
   CATEGORY_PREFIXES = {
       'general:'    => :general,
@@ -77,10 +78,22 @@ class Tag < ApplicationRecord
       'mtr:'        => :material,
       'meta:'       => :meta }.freeze
 
-  def tag_name(language_code) = tag_names.find_by(language_code:, primary_flg: true)
+  SYSTEM_TAG_NAMES = ['タグ希望', 'bot操作', 'ニジラー情報不詳', '動画', 'ニコニコ', 'YouTube'].freeze
+
+  def tag_name language_code
+    if tag_names.loaded?
+      tag_names.find { _1.language_code == language_code && _1.primary_flg }
+    else
+      tag_names.find_by(language_code:, primary_flg: true)
+    end
+  end
   def name(language_code) = tag_name(language_code)&.name
   def wiki_page = tag_name('ja')&.wiki_page
 
+  def system?
+    tag_name('ja')&.name.in?(SYSTEM_TAG_NAMES)
+  end
+
   def deprecated? = deprecated_at?
 
   def has_wiki = wiki_page.present?
@@ -232,6 +245,7 @@ class Tag < ApplicationRecord
 
     tag = Tag.create!(tag_name_id: tn.id, category:)
     tn.update!(tag:)
+    tag.association(:tag_names).reset
 
     tag
   rescue ActiveRecord::RecordNotUnique
@@ -307,6 +321,14 @@ class Tag < ApplicationRecord
 
   private
 
+  def tag_names_must_be_valid
+    tag_names.each do |tag_name|
+      next if tag_name.valid?
+
+      tag_name.errors[:name].each { errors.add :name, _1 }
+    end
+  end
+
   def category_must_be_deerjikist_with_deerjikists
     if !(deerjikist?) && deerjikists.exists?
       errors.add :category, 'ニジラーと紐づいてゐるタグはニジラー・カテゴリである必要があります．'
diff --git a/backend/app/representations/post_repr.rb b/backend/app/representations/post_repr.rb
index abd0dd2..4784526 100644
--- a/backend/app/representations/post_repr.rb
+++ b/backend/app/representations/post_repr.rb
@@ -91,7 +91,7 @@ module PostRepr
         post
         .post_tags
         .reject { _1.tag.deprecated? }
-        .sort_by { _1.tag.name(language_code) }
+        .sort_by { TagRepr.name_for(_1.tag, language_code) }
         .map { |post_tag|
           TagRepr.inline(post_tag.tag, language_code:).merge(
               'children' => [],
diff --git a/backend/app/representations/tag_repr.rb b/backend/app/representations/tag_repr.rb
index d54e743..9e3a42e 100644
--- a/backend/app/representations/tag_repr.rb
+++ b/backend/app/representations/tag_repr.rb
@@ -8,14 +8,18 @@ module TagRepr
   module_function
 
   def base tag, language_code: 'ja'
-    tag.as_json(BASE).merge(name: tag.name(language_code),
+    tag.as_json(BASE).merge(name: name_for(tag, language_code),
                             aliases: tag.snapshot_aliases(language_code),
                             parents: tag.parents.map { inline(_1, language_code:) })
   end
 
   def inline tag, language_code: 'ja'
-    tag.as_json(BASE).merge(name: tag.name(language_code), aliases: [], parents: [])
+    tag.as_json(BASE).merge(name: name_for(tag, language_code), aliases: [], parents: [])
   end
 
   def many(tags, language_code: 'ja') = tags.map { |tag| base(tag, language_code:) }
+
+  def name_for tag, language_code
+    tag.name(language_code) || (tag.system? ? tag.name('ja') : nil)
+  end
 end
diff --git a/backend/app/services/post_import_previewer.rb b/backend/app/services/post_import_previewer.rb
index a81a6b6..2431ded 100644
--- a/backend/app/services/post_import_previewer.rb
+++ b/backend/app/services/post_import_previewer.rb
@@ -463,7 +463,7 @@ class PostImportPreviewer
       TagName.canonicalise(locale, name.sub(/\[.*\]\z/, '')).first
     }
     existing = parsed.filter_map { known_tags[_1] }
-    deprecated = existing.select(&:deprecated?).map(&:name)
+    deprecated = existing.select(&:deprecated?).map { _1.name(locale.language_code) }
     errors[:tags] = ["廃止済みタグがあります: #{ deprecated.join(' ') }"] if deprecated.present?
   rescue Tag::SectionLiteralParseError
     errors[:tags] = ['タグ区間の記法が不正です．']
diff --git a/backend/app/services/tag_version_recorder.rb b/backend/app/services/tag_version_recorder.rb
index d5debc8..025c3d4 100644
--- a/backend/app/services/tag_version_recorder.rb
+++ b/backend/app/services/tag_version_recorder.rb
@@ -15,23 +15,24 @@ class TagVersionRecorder < VersionRecorder
 
   def snapshot_attributes
     names = snapshot_names
-    japanese_names = names.select { _1[:language_code] == 'ja' }
+    japanese_names = names.select { _1['language_code'] == 'ja' }
     compatibility_names = japanese_names.presence || names
 
-    { name: compatibility_names.find { _1[:primary_flg] }[:name],
+    { name: compatibility_names.find { _1['primary_flg'] }['name'],
       category: @record.category,
       deprecated_at: @record.deprecated_at,
-      aliases: compatibility_names.reject { _1[:primary_flg] }.map { _1[:name] }.join(' '),
+      aliases: compatibility_names.reject { _1['primary_flg'] }.map { _1['name'] }.join(' '),
       names:,
       parent_tag_ids: @record.snapshot_parent_tag_ids.join(' ') }
   end
 
   def snapshot_names
     @record.tag_names.order(:language_code, primary_flg: :desc).order(:name).map { |tag_name|
-      { language_code: tag_name.language_code,
-        name: tag_name.name,
-        script_code: tag_name.script_code,
-        primary_flg: tag_name.primary_flg }
+      { 'language_code' => tag_name.language_code,
+        'name' => tag_name.name,
+        'script_code' => tag_name.script_code,
+        'primary_flg' => tag_name.primary_flg,
+        'auto_generated' => tag_name.auto_generated }
     }
   end
 end
diff --git a/backend/db/migrate/20260922040000_add_names_to_tag_versions.rb b/backend/db/migrate/20260922040000_add_names_to_tag_versions.rb
index 4a84eb2..c64f9eb 100644
--- a/backend/db/migrate/20260922040000_add_names_to_tag_versions.rb
+++ b/backend/db/migrate/20260922040000_add_names_to_tag_versions.rb
@@ -13,7 +13,8 @@ class AddNamesToTagVersions < ActiveRecord::Migration[8.0]
           language_code: 'ja',
           name: version.name,
           script_code: 'Jpan',
-          primary_flg: true }]
+          primary_flg: true,
+          auto_generated: false }]
         names.concat(version.aliases.to_s.split.filter_map { |name|
           next if name.blank?
 
@@ -21,7 +22,8 @@ class AddNamesToTagVersions < ActiveRecord::Migration[8.0]
             language_code: 'ja',
             name:,
             script_code: 'Jpan',
-            primary_flg: false }
+            primary_flg: false,
+            auto_generated: false }
         })
         version.update_columns(names: names)
       end
diff --git a/backend/db/migrate/20260922050000_add_auto_generated_to_tag_names.rb b/backend/db/migrate/20260922050000_add_auto_generated_to_tag_names.rb
new file mode 100644
index 0000000..79cb3cc
--- /dev/null
+++ b/backend/db/migrate/20260922050000_add_auto_generated_to_tag_names.rb
@@ -0,0 +1,19 @@
+class AddAutoGeneratedToTagNames < ActiveRecord::Migration[8.0]
+  class TagVersion < ActiveRecord::Base
+    self.table_name = 'tag_versions'
+  end
+
+  def up
+    add_column :tag_names, :auto_generated, :boolean, null: false, default: false
+    TagVersion.reset_column_information
+
+    TagVersion.find_each do |version|
+      names = Array(version.names).map { |name| name.merge('auto_generated' => false) }
+      version.update_columns(names: names)
+    end
+  end
+
+  def down
+    remove_column :tag_names, :auto_generated
+  end
+end
diff --git a/backend/db/schema.rb b/backend/db/schema.rb
index 8862e73..bab1a8e 100644
--- a/backend/db/schema.rb
+++ b/backend/db/schema.rb
@@ -10,7 +10,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema[8.0].define(version: 2026_09_22_040000) do
+ActiveRecord::Schema[8.0].define(version: 2026_09_22_050000) do
   create_table "active_storage_attachments", charset: "utf8mb4", collation: "utf8mb4_0900_ai_ci", force: :cascade do |t|
     t.string "name", null: false
     t.string "record_type", null: false
@@ -454,6 +454,7 @@ ActiveRecord::Schema[8.0].define(version: 2026_09_22_040000) do
     t.datetime "created_at", null: false
     t.datetime "updated_at", null: false
     t.virtual "primary_tag_id", type: :bigint, as: "(case when `primary_flg` then `tag_id` else NULL end)"
+    t.boolean "auto_generated", default: false, null: false
     t.index ["canonical_id"], name: "index_tag_names_on_canonical_id"
     t.index ["language_code", "name"], name: "index_tag_names_on_language_code_and_name", unique: true
     t.index ["primary_tag_id", "language_code"], name: "index_tag_names_on_primary_tag_id_and_language_code", unique: true
diff --git a/backend/spec/factories/tag_names.rb b/backend/spec/factories/tag_names.rb
index f4d6890..0e98e3b 100644
--- a/backend/spec/factories/tag_names.rb
+++ b/backend/spec/factories/tag_names.rb
@@ -3,6 +3,7 @@ FactoryBot.define do
     language_code { 'ja' }
     script_code { 'Jpan' }
     primary_flg { true }
+    auto_generated { false }
     sequence(:name) { |number| "tag-#{ SecureRandom.hex(4) }-#{ number }" }
 
     trait :alias do
diff --git a/backend/spec/services/tag_version_recorder_spec.rb b/backend/spec/services/tag_version_recorder_spec.rb
index 9bec5d7..f97562c 100644
--- a/backend/spec/services/tag_version_recorder_spec.rb
+++ b/backend/spec/services/tag_version_recorder_spec.rb
@@ -23,13 +23,13 @@ RSpec.describe TagVersionRecorder do
 
     expect(version.names).to eq([
       { 'language_code' => 'en', 'name' => 'English name', 'script_code' => 'Latn',
-        'primary_flg' => true },
+        'primary_flg' => true, 'auto_generated' => false },
       { 'language_code' => 'en', 'name' => 'English alias', 'script_code' => 'Latn',
-        'primary_flg' => false },
+        'primary_flg' => false, 'auto_generated' => false },
       { 'language_code' => 'ja', 'name' => '日本語名', 'script_code' => 'Jpan',
-        'primary_flg' => true },
+        'primary_flg' => true, 'auto_generated' => false },
       { 'language_code' => 'ja', 'name' => '別名', 'script_code' => 'Jpan',
-        'primary_flg' => false }
+        'primary_flg' => false, 'auto_generated' => false }
     ])
   end
 
@@ -44,4 +44,13 @@ RSpec.describe TagVersionRecorder do
       hash_including('language_code' => 'en', 'name' => 'English name'))
     expect(updated.names).to include(hash_including('language_code' => 'en', 'name' => 'Renamed'))
   end
+
+  it 'does not create a version for an unchanged multilingual snapshot' do
+    described_class.record!(tag:, event_type: :create, created_by_user: user)
+
+    unchanged = described_class.record!(tag:, event_type: :update, created_by_user: user)
+
+    expect(unchanged.version_no).to eq(1)
+    expect(tag.reload.tag_versions.count).to eq(1)
+  end
 end