backend/app/controllers/gekanator_question_suggestions_controller.rb

@@ -12,9 +12,35 @@ class GekanatorQuestionSuggestionsController < ApplicationController
         answer: params.require(:answer))
 
     if suggestion.save
-      render json: { id: suggestion.id }, status: :created
+      render json: {
+        id: suggestion.id,
+        count: game.question_suggestions.count
+      }, status: :created
     else
       render_validation_error suggestion
     end
   end
+
+  def ai_convert
+    return head :not_found unless current_user&.admin?
+
+    suggestion = GekanatorQuestionSuggestion.find_by(id: params[:id])
+    return head :not_found unless suggestion
+    if Gekanator::AiRunBudget.exceeded_after_next_run?
+      suggestion.gekanator_ai_runs.create!(
+          model: 'budget_guard',
+          status: 'blocked_budget',
+          input_tokens: 0,
+          output_tokens: 0,
+          estimated_cost_jpy: 0)
+      return head :payment_required
+    end
+
+    Gekanator::QuestionSuggestionAiConverter.call(
+        suggestion: suggestion,
+        user: current_user)
+    head :no_content
+  rescue NotImplementedError
+    head :not_implemented
+  end
 end

backend/app/controllers/gekanator_questions_controller.rb

@@ -0,0 +1,57 @@
+class GekanatorQuestionsController < ApplicationController
+  def index
+    return head :not_found unless current_user&.admin?
+
+    questions = GekanatorQuestion.accepted.order(priority_weight: :desc, id: :asc)
+
+    render json: {
+      questions: questions.map { |question| question_json(question) }
+    }
+  end
+
+  private
+
+  def question_json question
+    {
+      id: question_id_for(question),
+      text: question.text,
+      kind: question.kind,
+      condition: condition_json(question.condition),
+      source: question.source,
+      priority_weight: question.priority_weight
+    }
+  end
+
+  def question_id_for question
+    condition = condition_json(question.condition).deep_symbolize_keys
+
+    case condition[:type]
+    when 'tag'
+      "tag:#{ condition[:key] }"
+    when 'source'
+      "source:#{ condition[:host] }"
+    when 'original-year'
+      "original-year:#{ condition[:year] }"
+    when 'original-month'
+      "original-month:#{ condition[:month] }"
+    when 'original-month-day'
+      "original-month-day:#{ condition[:monthDay] || condition[:month_day] }"
+    when 'title-length-greater-than'
+      "title:length-greater-than:#{ condition[:length] }"
+    when 'title-has-ascii'
+      'title:ascii'
+    else
+      "catalog:#{ question.id }"
+    end
+  end
+
+  def condition_json condition
+    json = condition.deep_dup.as_json
+
+    if json['type'] == 'original-month-day' && json['monthDay'].blank?
+      json['monthDay'] = json.delete('month_day')
+    end
+
+    json
+  end
+end

backend/app/models/gekanator_ai_run.rb

@@ -0,0 +1,21 @@
+class GekanatorAiRun < ApplicationRecord
+  STATUSES = ['pending', 'running', 'succeeded', 'failed', 'blocked_budget'].freeze
+
+  belongs_to :gekanator_question_suggestion
+
+  validates :model, presence: true, length: { maximum: 255 }
+  validates :status, presence: true, inclusion: { in: STATUSES }
+  validates :input_tokens,
+            presence: true,
+            numericality: { only_integer: true, greater_than_or_equal_to: 0 }
+  validates :output_tokens,
+            presence: true,
+            numericality: { only_integer: true, greater_than_or_equal_to: 0 }
+  validates :estimated_cost_jpy,
+            presence: true,
+            numericality: { greater_than_or_equal_to: 0 }
+
+  scope :this_month, lambda {
+    where(created_at: Time.current.beginning_of_month..Time.current.end_of_month)
+  }
+end

backend/app/models/gekanator_question.rb

@@ -0,0 +1,19 @@
+class GekanatorQuestion < ApplicationRecord
+  KINDS = ['tag', 'source', 'title', 'original_date'].freeze
+  SOURCES = ['user_suggested', 'ai_generated', 'admin_curated'].freeze
+  STATUSES = ['pending', 'accepted', 'rejected'].freeze
+
+  belongs_to :gekanator_question_suggestion, optional: true
+  belongs_to :created_by, class_name: 'User', optional: true
+
+  validates :kind, presence: true, inclusion: { in: KINDS }
+  validates :source, presence: true, inclusion: { in: SOURCES }
+  validates :status, presence: true, inclusion: { in: STATUSES }
+  validates :text, presence: true, length: { maximum: 1000 }
+  validates :condition, presence: true
+  validates :priority_weight,
+            presence: true,
+            numericality: { greater_than: 0 }
+
+  scope :accepted, -> { where(status: 'accepted') }
+end

backend/app/models/gekanator_question_suggestion.rb

@@ -1,9 +1,11 @@
 class GekanatorQuestionSuggestion < ApplicationRecord
-  MAX_QUESTIONS_PER_GAME = 1
+  MAX_QUESTIONS_PER_GAME = 3
   ANSWERS = ['yes', 'no', 'partial', 'probably_no', 'unknown'].freeze
 
   belongs_to :gekanator_game
   belongs_to :user
+  has_many :gekanator_questions, dependent: :nullify
+  has_many :gekanator_ai_runs, dependent: :destroy
 
   validates :question_text, presence: true, length: { maximum: 1000 }
   validates :answer, presence: true, inclusion: { in: ANSWERS }

backend/app/services/gekanator/ai_run_budget.rb

@@ -0,0 +1,22 @@
+module Gekanator
+  class AiRunBudget
+    MONTHLY_LIMIT_JPY = BigDecimal('450').freeze
+    MAX_RUN_ESTIMATED_COST_JPY = BigDecimal('5').freeze
+
+    def self.remaining_monthly_budget_jpy
+      MONTHLY_LIMIT_JPY - monthly_cost_jpy
+    end
+
+    def self.monthly_cost_jpy
+      GekanatorAiRun.this_month.sum(:estimated_cost_jpy)
+    end
+
+    def self.exceeded?
+      monthly_cost_jpy >= MONTHLY_LIMIT_JPY
+    end
+
+    def self.exceeded_after_next_run?
+      monthly_cost_jpy + MAX_RUN_ESTIMATED_COST_JPY >= MONTHLY_LIMIT_JPY
+    end
+  end
+end

backend/app/services/gekanator/question_suggestion_ai_converter.rb

@@ -0,0 +1,18 @@
+module Gekanator
+  class QuestionSuggestionAiConverter
+    def self.call(...) = new(...).call
+
+    def initialize suggestion:, user:
+      @suggestion = suggestion
+      @user = user
+    end
+
+    def call
+      raise NotImplementedError, 'AI question conversion is not implemented yet.'
+    end
+
+    private
+
+    attr_reader :suggestion, :user
+  end
+end

backend/config/routes.rb

@@ -66,9 +66,14 @@ Rails.application.routes.draw do
   namespace :gekanator do
     resources :games, only: [:create], controller: '/gekanator_games'
     resources :posts, only: [:index], controller: '/gekanator_posts'
+    resources :questions, only: [:index], controller: '/gekanator_questions'
     resources :question_suggestions,
               only: [:create],
-              controller: '/gekanator_question_suggestions'
+              controller: '/gekanator_question_suggestions' do
+      member do
+        post :ai_convert
+      end
+    end
   end
 
   resources :users, only: [:create, :update] do

backend/db/migrate/20260609000000_create_gekanator_questions.rb

@@ -0,0 +1,19 @@
+class CreateGekanatorQuestions < ActiveRecord::Migration[8.0]
+  def change
+    create_table :gekanator_questions do |t|
+      t.string :text, null: false
+      t.string :kind, null: false
+      t.json :condition, null: false
+      t.string :source, null: false, default: 'ai_generated'
+      t.string :status, null: false, default: 'pending'
+      t.float :priority_weight, null: false, default: 1.0
+      t.references :gekanator_question_suggestion,
+                   null: true,
+                   foreign_key: true
+      t.references :created_by,
+                   null: true,
+                   foreign_key: { to_table: :users }
+      t.timestamps
+    end
+  end
+end

backend/db/migrate/20260609001000_create_gekanator_ai_runs.rb

@@ -0,0 +1,13 @@
+class CreateGekanatorAiRuns < ActiveRecord::Migration[8.0]
+  def change
+    create_table :gekanator_ai_runs do |t|
+      t.string :model, null: false
+      t.integer :input_tokens, null: false, default: 0
+      t.integer :output_tokens, null: false, default: 0
+      t.decimal :estimated_cost_jpy, precision: 8, scale: 3, null: false, default: 0
+      t.string :status, null: false, default: 'pending'
+      t.references :gekanator_question_suggestion, null: false, foreign_key: true
+      t.timestamps
+    end
+  end
+end

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_06_08_002000) do
+ActiveRecord::Schema[8.0].define(version: 2026_06_09_001000) 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
@@ -48,6 +48,18 @@ ActiveRecord::Schema[8.0].define(version: 2026_06_08_002000) do
     t.index ["tag_id"], name: "index_deerjikists_on_tag_id"
   end
 
+  create_table "gekanator_ai_runs", charset: "utf8mb4", collation: "utf8mb4_0900_ai_ci", force: :cascade do |t|
+    t.string "model", null: false
+    t.integer "input_tokens", default: 0, null: false
+    t.integer "output_tokens", default: 0, null: false
+    t.decimal "estimated_cost_jpy", precision: 8, scale: 3, default: "0.0", null: false
+    t.string "status", default: "pending", null: false
+    t.bigint "gekanator_question_suggestion_id", null: false
+    t.datetime "created_at", null: false
+    t.datetime "updated_at", null: false
+    t.index ["gekanator_question_suggestion_id"], name: "index_gekanator_ai_runs_on_gekanator_question_suggestion_id"
+  end
+
   create_table "gekanator_games", charset: "utf8mb4", collation: "utf8mb4_0900_ai_ci", force: :cascade do |t|
     t.bigint "user_id", null: false
     t.bigint "guessed_post_id", null: false
@@ -75,6 +87,21 @@ ActiveRecord::Schema[8.0].define(version: 2026_06_08_002000) do
     t.index ["user_id"], name: "index_gekanator_question_suggestions_on_user_id"
   end
 
+  create_table "gekanator_questions", charset: "utf8mb4", collation: "utf8mb4_0900_ai_ci", force: :cascade do |t|
+    t.string "text", null: false
+    t.string "kind", null: false
+    t.json "condition", null: false
+    t.string "source", default: "ai_generated", null: false
+    t.string "status", default: "pending", null: false
+    t.float "priority_weight", default: 1.0, null: false
+    t.bigint "gekanator_question_suggestion_id"
+    t.bigint "created_by_id"
+    t.datetime "created_at", null: false
+    t.datetime "updated_at", null: false
+    t.index ["created_by_id"], name: "index_gekanator_questions_on_created_by_id"
+    t.index ["gekanator_question_suggestion_id"], name: "index_gekanator_questions_on_gekanator_question_suggestion_id"
+  end
+
   create_table "ip_addresses", charset: "utf8mb4", collation: "utf8mb4_0900_ai_ci", force: :cascade do |t|
     t.binary "ip_address", limit: 16, null: false
     t.datetime "banned_at"
@@ -164,6 +191,19 @@ ActiveRecord::Schema[8.0].define(version: 2026_06_08_002000) do
     t.index ["target_post_id"], name: "index_post_similarities_on_target_post_id"
   end
 
+  create_table "post_tag_sections", primary_key: ["post_id", "tag_id", "begin_ms"], charset: "utf8mb4", collation: "utf8mb4_0900_ai_ci", force: :cascade do |t|
+    t.bigint "post_id", null: false
+    t.bigint "tag_id", null: false
+    t.integer "begin_ms", null: false
+    t.integer "end_ms", null: false
+    t.datetime "created_at", null: false
+    t.datetime "updated_at", null: false
+    t.index ["post_id", "begin_ms"], name: "idx_post_tag_sections_post_id_begin_ms"
+    t.index ["tag_id"], name: "fk_rails_8be3847903"
+    t.check_constraint "`begin_ms` < `end_ms`", name: "chk_post_tag_sections_end_ms_after_begin_ms"
+    t.check_constraint "`begin_ms` >= 0", name: "chk_post_tag_sections_begin_ms_natural"
+  end
+
   create_table "post_tags", charset: "utf8mb4", collation: "utf8mb4_0900_ai_ci", force: :cascade do |t|
     t.bigint "post_id", null: false
     t.bigint "tag_id", null: false
@@ -214,8 +254,11 @@ ActiveRecord::Schema[8.0].define(version: 2026_06_08_002000) do
     t.datetime "original_created_before"
     t.datetime "updated_at", null: false
     t.integer "version_no", null: false
+    t.integer "video_ms"
     t.index ["uploaded_user_id"], name: "index_posts_on_uploaded_user_id"
     t.index ["url"], name: "index_posts_on_url", unique: true
+    t.index ["video_ms", "id"], name: "idx_posts_video_ms_id"
+    t.check_constraint "(`video_ms` is null) or (`video_ms` > 0)", name: "chk_posts_video_ms_positive"
     t.check_constraint "`version_no` > 0", name: "chk_posts_version_no_positive"
   end
 
@@ -366,6 +409,7 @@ ActiveRecord::Schema[8.0].define(version: 2026_06_08_002000) do
     t.datetime "created_at", null: false
     t.datetime "updated_at", null: false
     t.index ["expires_at"], name: "index_theatre_watching_users_on_expires_at"
+    t.index ["theatre_id", "expires_at"], name: "idx_on_theatre_id_skip_expires_at_4c8de1dd42"
     t.index ["theatre_id", "expires_at"], name: "index_theatre_watching_users_on_theatre_id_and_expires_at"
     t.index ["theatre_id"], name: "index_theatre_watching_users_on_theatre_id"
     t.index ["user_id"], name: "index_theatre_watching_users_on_user_id"
@@ -505,11 +549,14 @@ ActiveRecord::Schema[8.0].define(version: 2026_06_08_002000) do
 
   add_foreign_key "active_storage_attachments", "active_storage_blobs", column: "blob_id"
   add_foreign_key "active_storage_variant_records", "active_storage_blobs", column: "blob_id"
+  add_foreign_key "gekanator_ai_runs", "gekanator_question_suggestions"
   add_foreign_key "gekanator_games", "posts", column: "correct_post_id"
   add_foreign_key "gekanator_games", "posts", column: "guessed_post_id"
   add_foreign_key "gekanator_games", "users"
   add_foreign_key "gekanator_question_suggestions", "gekanator_games", on_delete: :cascade
   add_foreign_key "gekanator_question_suggestions", "users"
+  add_foreign_key "gekanator_questions", "gekanator_question_suggestions"
+  add_foreign_key "gekanator_questions", "users", column: "created_by_id"
   add_foreign_key "material_versions", "materials"
   add_foreign_key "material_versions", "materials", column: "parent_id"
   add_foreign_key "material_versions", "tags"
@@ -527,6 +574,8 @@ ActiveRecord::Schema[8.0].define(version: 2026_06_08_002000) do
   add_foreign_key "post_implications", "posts", column: "parent_post_id"
   add_foreign_key "post_similarities", "posts"
   add_foreign_key "post_similarities", "posts", column: "target_post_id"
+  add_foreign_key "post_tag_sections", "posts"
+  add_foreign_key "post_tag_sections", "tags"
   add_foreign_key "post_tags", "posts"
   add_foreign_key "post_tags", "tags"
   add_foreign_key "post_tags", "users", column: "created_user_id"

frontend/src/lib/gekanator.ts

@@ -22,6 +22,12 @@ export type GekanatorQuestionKind =
     | 'title'
     | 'original_date'
 
+export type GekanatorQuestionSource =
+    | 'default'
+    | 'user_suggested'
+    | 'ai_generated'
+    | 'admin_curated'
+
 export type GekanatorQuestionCondition =
     | { type: 'tag'; key: string }
     | { type: 'source'; host: string }
@@ -35,13 +41,17 @@ export type StoredGekanatorQuestion = {
     id:              string
     text:            string
     kind:            GekanatorQuestionKind
-    condition:  GekanatorQuestionCondition }
+    condition:       GekanatorQuestionCondition
+    source?:         GekanatorQuestionSource
+    priorityWeight?: number }
 
 export type GekanatorQuestion = {
     id:              string
     text:            string
     kind:            GekanatorQuestionKind
     condition:       GekanatorQuestionCondition
+    source:          GekanatorQuestionSource
+    priorityWeight:  number
     test:            (post: Post) => boolean }
 
 const countBy = <T extends string | number> (values: T[]): Map<T, number> => {
@@ -188,6 +198,8 @@ export const restoreGekanatorQuestion = (
     question:  StoredGekanatorQuestion,
 ): GekanatorQuestion => ({
   ...question,
+  source: question.source ?? 'default',
+  priorityWeight: question.priorityWeight ?? 1,
   test: (post: Post) => questionMatches (post, question.condition) })
 
 
@@ -197,7 +209,9 @@ export const storeGekanatorQuestion = (
   id: question.id,
   text: question.text,
   kind: question.kind,
-  condition: question.condition })
+  condition: question.condition,
+  source: question.source,
+  priorityWeight: question.priorityWeight })
 
 
 export const fetchGekanatorPosts = async (): Promise<Post[]> => {
@@ -206,6 +220,12 @@ export const fetchGekanatorPosts = async (): Promise<Post[]> => {
 }
 
 
+export const fetchGekanatorQuestions = async (): Promise<StoredGekanatorQuestion[]> => {
+  const data = await apiGet<{ questions: StoredGekanatorQuestion[] }> ('/gekanator/questions')
+  return data.questions
+}
+
+
 export const buildGekanatorQuestions = (posts: Post[]): GekanatorQuestion[] => {
   const tagCounts = countBy (posts.flatMap (post =>
       post.tags
@@ -248,6 +268,8 @@ export const buildGekanatorQuestions = (posts: Post[]): GekanatorQuestion[] => {
 	    text: tagQuestionText (category, label),
 	    kind: 'tag' as const,
 	    condition: { type: 'tag' as const, key: String (key) },
+	    source: 'default' as const,
+	    priorityWeight: 1,
 	    test: (post: Post) => questionableTag (post, String (key)) }
       })
 
@@ -259,6 +281,8 @@ export const buildGekanatorQuestions = (posts: Post[]): GekanatorQuestion[] => {
 	  text: `${ host } の投稿を思ひ浮かべてゐる?`,
 	  kind: 'source' as const,
 	  condition: { type: 'source' as const, host },
+	  source: 'default' as const,
+	  priorityWeight: 1,
 	  test: (post: Post) => hostOf (post) === host }))
 
   const originalYearQuestions = usefulEntries (originalYears)
@@ -269,6 +293,8 @@ export const buildGekanatorQuestions = (posts: Post[]): GekanatorQuestion[] => {
 	  text: `オリジナルの投稿年は ${ year } 年?`,
 	  kind: 'original_date' as const,
 	  condition: { type: 'original-year' as const, year },
+	  source: 'default' as const,
+	  priorityWeight: 1,
 	  test: (post: Post) => originalYearOf (post) === year }))
 
   const originalMonthQuestions = usefulEntries (originalMonths)
@@ -279,6 +305,8 @@ export const buildGekanatorQuestions = (posts: Post[]): GekanatorQuestion[] => {
 	  text: `オリジナルの投稿月は ${ month } 月?`,
 	  kind: 'original_date' as const,
 	  condition: { type: 'original-month' as const, month },
+	  source: 'default' as const,
+	  priorityWeight: 1,
 	  test: (post: Post) => originalMonthOf (post) === month }))
 
   const originalMonthDayQuestions = usefulEntries (originalMonthDays)
@@ -292,6 +320,8 @@ export const buildGekanatorQuestions = (posts: Post[]): GekanatorQuestion[] => {
 	    text: `オリジナルの投稿日は ${ month } 月 ${ day } 日?`,
 	    kind: 'original_date' as const,
 	    condition: { type: 'original-month-day' as const, monthDay: String (monthDay) },
+	    source: 'default' as const,
+	    priorityWeight: 1,
 	    test: (post: Post) => originalMonthDayOf (post) === monthDay }
       })
 
@@ -303,12 +333,16 @@ export const buildGekanatorQuestions = (posts: Post[]): GekanatorQuestion[] => {
 	  condition: {
 	      type: 'title-length-greater-than' as const,
 	      length: titleLengthMedian },
+	  source: 'default' as const,
+	  priorityWeight: 1,
 	  test: (post: Post) => (post.title?.length ?? 0) > titleLengthMedian },
       {
 	  id:   'title:ascii',
 	  text: '題名に英数字が混じってゐる?',
 	  kind: 'title' as const,
 	  condition: { type: 'title-has-ascii' as const },
+	  source: 'default' as const,
+	  priorityWeight: 1,
 	  test: (post: Post) => /[A-Za-z0-9]/.test (post.title ?? '') }]
       .filter (question => {
 	const yes = posts.filter (post => question.test (post)).length
@@ -354,7 +388,7 @@ export const saveGekanatorQuestionSuggestion = async ({
     gekanatorGameId:  number
     questionText:     string
     answer:           GekanatorAnswerValue
-}): Promise<{ id: number }> =>
+}): Promise<{ id: number; count: number }> =>
     await apiPost ('/gekanator/question_suggestions', {
 	gekanator_game_id: gekanatorGameId,
 	question_text: questionText,

frontend/src/lib/queryKeys.ts

@@ -10,7 +10,8 @@ export const postsKeys = {
 
 export const gekanatorKeys = {
     root:      ['gekanator'] as const,
-    posts:  () => ['gekanator', 'posts'] as const }
+    posts:     () => ['gekanator', 'posts'] as const,
+    questions: () => ['gekanator', 'questions'] as const }
 
 export const tagsKeys = {
     root:         ['tags'] as const,

frontend/src/pages/GekanatorPage.tsx

@@ -6,6 +6,7 @@ import PrefetchLink from '@/components/PrefetchLink'
 import MainArea from '@/components/layout/MainArea'
 import { SITE_TITLE } from '@/config'
 import { buildGekanatorQuestions,
+	 fetchGekanatorQuestions,
 	 fetchGekanatorPosts,
 	 restoreGekanatorQuestion,
 	 saveGekanatorGame,
@@ -83,8 +84,10 @@ type StoredGekanatorGame = {
     reviewGuessedPostId:         number | null
     reviewCorrectPostId:         number | null
     savedGameId:                 number | null
+    gameSeed?:                   string
     questionSuggestion:          string
-    questionSuggestionAnswer:    GekanatorAnswerValue }
+    questionSuggestionAnswer:    GekanatorAnswerValue
+    questionSuggestionCount?:    number }
 
 const answerOptions: AnswerOption[] = [
     { label: 'はい', value: 'yes' },
@@ -104,6 +107,84 @@ const hardMaxQuestions = 80
 const softenedAnswerWeight = .35
 const confidenceTemperature = 6
 const gameStorageKey = 'gekanator:game:v1'
+const maxQuestionSuggestionsPerGame = 3
+
+const sourcePriorityOffset = (question: GekanatorQuestion): number => {
+  switch (question.source)
+  {
+  case 'user_suggested':
+    return -1.2
+  case 'admin_curated':
+    return -0.8
+  case 'ai_generated':
+    return -0.6
+  default:
+    return 0
+  }
+}
+
+
+const priorityWeightOffset = (question: GekanatorQuestion): number =>
+    (question.priorityWeight - 1) * -.8
+
+
+const createGameSeed = (): string => {
+  if (typeof crypto !== 'undefined' && typeof crypto.randomUUID === 'function')
+    return crypto.randomUUID ()
+
+  return `${ Date.now () }:${ Math.random ().toString (36).slice (2) }`
+}
+
+
+const sourcePriorityForMerge = (question: GekanatorQuestion): number => {
+  switch (question.source)
+  {
+  case 'user_suggested':
+    return 3
+  case 'admin_curated':
+    return 3
+  case 'ai_generated':
+    return 3
+  default:
+    return 1
+  }
+}
+
+
+const shouldReplaceMergedQuestion = (
+    current:    GekanatorQuestion | undefined,
+    candidate:  GekanatorQuestion,
+): boolean => {
+  if (!(current))
+    return true
+
+  const currentSourcePriority = sourcePriorityForMerge (current)
+  const candidateSourcePriority = sourcePriorityForMerge (candidate)
+  if (candidateSourcePriority !== currentSourcePriority)
+    return candidateSourcePriority > currentSourcePriority
+
+  if (candidate.priorityWeight !== current.priorityWeight)
+    return candidate.priorityWeight > current.priorityWeight
+
+  return true
+}
+
+
+const hashString = (value: string): number => {
+  let hash = 2166136261
+
+  for (let i = 0; i < value.length; i += 1)
+    {
+	hash ^= value.charCodeAt (i)
+	hash = Math.imul (hash, 16777619)
+    }
+
+  return hash >>> 0
+}
+
+
+const deterministicUnitFloat = (seed: string): number =>
+    hashString (seed) / 4294967295
 
 
 const clearStoredGame = (): void => {
@@ -326,7 +407,11 @@ const previewAnswer = ({
 
 const mergeQuestions = (questions: GekanatorQuestion[]): GekanatorQuestion[] => {
   const byId = new Map<string, GekanatorQuestion> ()
-  questions.forEach (question => byId.set (question.id, question))
+  questions.forEach (question => {
+    const current = byId.get (question.id)
+    if (shouldReplaceMergedQuestion (current, question))
+      byId.set (question.id, question)
+  })
   return [...byId.values ()]
 }
 
@@ -367,11 +452,13 @@ const chooseQuestion = ({
     questions,
     scores,
     askedIds,
+    gameSeed,
 }: {
     posts:      Post[]
     questions:  GekanatorQuestion[]
     scores:     Map<number, number>
     askedIds:   Set<string>
+    gameSeed:   string
 }): GekanatorQuestion | null => {
   const scoredPosts = posts
       .map (post => ({ post, score: scores.get (post.id) ?? 0 }))
@@ -440,12 +527,16 @@ const chooseQuestion = ({
 	const tagPenalty = question.kind === 'tag' && nonTagCount < 4 ? .12 : 0
 	const minSide = candidates.length < 10 ? 1 : Math.max (3, candidates.length * .08)
 	const narrowPenalty = yes < minSide || no < minSide ? .15 : 0
+	const sourceBonus = sourcePriorityOffset (question)
+	const priorityBonus = priorityWeightOffset (question)
 
 	return { question,
 		 score: weightedSplitScore * 100
 		     + unweightedSplitScore * 8
 		     + tagPenalty
-		     + narrowPenalty,
+		     + narrowPenalty
+		     + sourceBonus
+		     + priorityBonus,
 		 narrow: narrowPenalty > 0 }
       })
       .filter ((item): item is {
@@ -458,8 +549,35 @@ const chooseQuestion = ({
   const unansweredQuestions =
       questions.filter (question => !(askedIds.has (question.id)))
   const ranked = rank (unansweredQuestions, scoredPosts, normalisedWeightedPosts)
+  const pool = (
+      ranked.some (item => !(item.narrow))
+	? ranked.filter (item => !(item.narrow))
+	: ranked)
+      .slice (0, 12)
 
-  return (ranked.find (item => !(item.narrow)) ?? ranked[0])?.question ?? null
+  if (pool.length === 0)
+    return null
+
+  const bestScore = pool[0]?.score ?? 0
+  const weightedPool = pool.map (item => ({
+      ...item,
+      weight: Math.exp ((bestScore - item.score) / 1.8) }))
+  const totalPoolWeight =
+      weightedPool.reduce ((sum, item) => sum + item.weight, 0) || 1
+  const seed = `${ gameSeed }:${ [...askedIds].sort ().join ('|') }:${
+      weightedPool.map (item => `${ item.question.id }:${ item.score.toFixed (4) }`).join ('|')
+  }`
+  const target = deterministicUnitFloat (seed) * totalPoolWeight
+  let cumulative = 0
+
+  for (const item of weightedPool)
+    {
+	cumulative += item.weight
+	if (target <= cumulative)
+	  return item.question
+    }
+
+  return weightedPool[weightedPool.length - 1]?.question ?? null
 }
 
 
@@ -501,6 +619,8 @@ const expectedAnswerFor = (
 
 const GekanatorPage: FC = () => {
   const storedGame = useMemo (loadStoredGame, [])
+  const [gameSeed, setGameSeed] = useState (
+      storedGame?.gameSeed ?? createGameSeed ())
   const [phase, setPhase] = useState<Phase> (storedGame?.phase ?? 'intro')
   const [scores, setScores] = useState<Map<number, number>> (
       () => new Map (storedGame?.scores ?? []))
@@ -540,24 +660,37 @@ const GekanatorPage: FC = () => {
       storedGame?.questionSuggestion ?? '')
   const [questionSuggestionAnswer, setQuestionSuggestionAnswer] =
       useState<GekanatorAnswerValue> (storedGame?.questionSuggestionAnswer ?? 'yes')
+  const [questionSuggestionCount, setQuestionSuggestionCount] = useState (
+      storedGame?.questionSuggestionCount ?? 0)
   const [history, setHistory] = useState<GameSnapshot[]> ([])
 
   const { data: posts = [], isLoading, error } = useQuery ({
       queryKey: gekanatorKeys.posts (),
       queryFn: fetchGekanatorPosts })
+  const { data: acceptedQuestions = [], isFetched: acceptedQuestionsFetched } = useQuery ({
+      queryKey: gekanatorKeys.questions (),
+      queryFn: fetchGekanatorQuestions,
+      select: questions => questions.map (restoreGekanatorQuestion) })
 
   useEffect (() => {
-    if (posts.length === 0 || storedAskedQuestionBankIds.length === 0)
+    if (
+	posts.length === 0
+	|| storedAskedQuestionBankIds.length === 0
+	|| !(acceptedQuestionsFetched)
+    )
       return
 
     const questionById = new Map (
-	buildGekanatorQuestions (posts).map (question => [question.id, question]))
+	mergeQuestions ([
+	    ...buildGekanatorQuestions (posts),
+	    ...acceptedQuestions])
+	    .map (question => [question.id, question]))
     setAskedQuestionBank (
 	storedAskedQuestionBankIds
 	    .map (questionId => questionById.get (questionId))
 	    .filter ((question): question is GekanatorQuestion => question !== undefined))
     setStoredAskedQuestionBankIds ([])
-  }, [posts, storedAskedQuestionBankIds])
+  }, [posts, storedAskedQuestionBankIds, acceptedQuestions, acceptedQuestionsFetched])
 
   useEffect (() => {
     if (!(isStoredPhase (phase)) && answers.length === 0)
@@ -585,8 +718,10 @@ const GekanatorPage: FC = () => {
 	reviewGuessedPostId,
 	reviewCorrectPostId,
 	savedGameId,
+	gameSeed,
 	questionSuggestion,
-	questionSuggestionAnswer }
+	questionSuggestionAnswer,
+	questionSuggestionCount }
 
     try
     {
@@ -615,8 +750,10 @@ const GekanatorPage: FC = () => {
       reviewGuessedPostId,
       reviewCorrectPostId,
       savedGameId,
+      gameSeed,
       questionSuggestion,
-      questionSuggestionAnswer])
+      questionSuggestionAnswer,
+      questionSuggestionCount])
 
   const eligiblePosts = useMemo (
       () => candidatePostsFor ({
@@ -627,8 +764,10 @@ const GekanatorPage: FC = () => {
 	  rejectedPostIds }),
       [posts, askedQuestionBank, answers, softenedQuestionIds, rejectedPostIds])
   const questions = useMemo (
-      () => buildGekanatorQuestions (eligiblePosts.length > 1 ? eligiblePosts : posts),
-      [eligiblePosts, posts])
+      () => mergeQuestions ([
+	  ...buildGekanatorQuestions (eligiblePosts.length > 1 ? eligiblePosts : posts),
+	  ...acceptedQuestions]),
+      [acceptedQuestions, eligiblePosts, posts])
   const scoringQuestions = useMemo (() => {
     return mergeQuestions ([...questions, ...askedQuestionBank])
   }, [questions, askedQuestionBank])
@@ -651,7 +790,11 @@ const GekanatorPage: FC = () => {
       .slice (0, 3),
       [eligiblePosts, scores])
   const currentQuestion = chooseQuestion ({
-      posts: questionPosts, questions: scoringQuestions, scores, askedIds })
+      posts: questionPosts,
+      questions: scoringQuestions,
+      scores,
+      askedIds,
+      gameSeed })
   const answerPreviews = useMemo (
       () => currentQuestion
 	  ? answerOptions.map (option => previewAnswer ({
@@ -681,10 +824,10 @@ const GekanatorPage: FC = () => {
       }})
   const questionSuggestionMutation = useMutation ({
       mutationFn: saveGekanatorQuestionSuggestion,
-      onSuccess: () => {
+      onSuccess: data => {
+	setQuestionSuggestionCount (data.count)
 	setQuestionSuggestion ('')
 	setQuestionSuggestionAnswer ('yes')
-	reset ()
       }})
 
   const reset = () => {
@@ -707,8 +850,10 @@ const GekanatorPage: FC = () => {
     setReviewGuessedPostId (null)
     setReviewCorrectPostId (null)
     setSavedGameId (null)
+    setGameSeed (createGameSeed ())
     setQuestionSuggestion ('')
     setQuestionSuggestionAnswer ('yes')
+    setQuestionSuggestionCount (0)
     setHistory ([])
   }
 
@@ -740,6 +885,7 @@ const GekanatorPage: FC = () => {
     let recoveredScoringQuestions = mergeQuestions ([
 	...buildGekanatorQuestions (
 	    recoveredEligiblePosts.length > 1 ? recoveredEligiblePosts : posts),
+	...acceptedQuestions,
 	...nextAskedQuestionBank])
 
     while (
@@ -750,7 +896,8 @@ const GekanatorPage: FC = () => {
 		posts: recoveredEligiblePosts,
 		questions: recoveredScoringQuestions,
 		scores: recoveredScores,
-		askedIds: nextAskedIds })))
+		askedIds: nextAskedIds,
+		gameSeed })))
     )
       {
 	if (nextAnswers.length >= hardMaxQuestions)
@@ -778,6 +925,7 @@ const GekanatorPage: FC = () => {
 	recoveredScoringQuestions = mergeQuestions ([
 	    ...buildGekanatorQuestions (
 		recoveredEligiblePosts.length > 1 ? recoveredEligiblePosts : posts),
+	    ...acceptedQuestions,
 	    ...nextAskedQuestionBank])
       }
 
@@ -934,9 +1082,23 @@ const GekanatorPage: FC = () => {
     saveReviewedResult (() => setPhase ('learned'))
   }
 
+  const restartFromQuestionSuggestion = () => {
+    if (savedGameId !== null)
+      {
+	reset ()
+	return
+      }
+
+    saveReviewedResult (reset)
+  }
+
   const submitQuestionSuggestion = () => {
     const questionText = questionSuggestion.trim ()
-    if (!(questionText) || questionSuggestionMutation.isPending)
+    if (
+	!(questionText)
+	|| questionSuggestionMutation.isPending
+	|| questionSuggestionCount >= maxQuestionSuggestionsPerGame
+    )
       return
 
     saveReviewedResult (gekanatorGameId => {
@@ -1008,7 +1170,8 @@ const GekanatorPage: FC = () => {
 	    : nonRejectedPosts,
 	questions: recovered.scoringQuestions,
 	scores: recovered.scores,
-	askedIds })
+	askedIds,
+	gameSeed })
 
     if (nextQuestion)
       {
@@ -1445,6 +1608,9 @@ const GekanatorPage: FC = () => {
 		      <div>
 			<p className="text-sm text-neutral-500">質問追加</p>
 			<p className="text-xl font-bold">どんな質問なら見分けられさう?</p>
+			<p className="text-sm text-neutral-600 dark:text-neutral-300">
+			  追加済み {questionSuggestionCount} / {maxQuestionSuggestionsPerGame}
+			</p>
 		      </div>
 		      <label className="block space-y-2">
 			<span className="font-bold">質問候補</span>
@@ -1483,18 +1649,33 @@ const GekanatorPage: FC = () => {
 			</button>
 			<button
 			    type="button"
-			    className="rounded bg-pink-600 px-4 py-2 font-bold text-white
-				       hover:bg-pink-500 disabled:opacity-50"
+			    className="rounded border border-yellow-300 px-4 py-2
+				       hover:bg-yellow-100 dark:border-red-700
+				       dark:hover:bg-red-900 disabled:opacity-50"
 			    disabled={
-			      reviewCorrectPostId === null
+			      questionSuggestionCount >= maxQuestionSuggestionsPerGame
+			      || reviewCorrectPostId === null
 			      || questionSuggestion.trim () === ''
 			      || saveMutation.isPending
 			      || questionSuggestionMutation.isPending
 			    }
 			    onClick={submitQuestionSuggestion}>
-			  追加してもう一度
+			  追加
+			</button>
+			<button
+			    type="button"
+			    className="rounded bg-pink-600 px-4 py-2 font-bold text-white
+				       hover:bg-pink-500 disabled:opacity-50"
+			    disabled={saveMutation.isPending
+				      || questionSuggestionMutation.isPending}
+			    onClick={restartFromQuestionSuggestion}>
+			  もう一度
 			</button>
 		      </div>
+		      {questionSuggestionCount >= maxQuestionSuggestionsPerGame && (
+			  <p className="text-sm text-neutral-600 dark:text-neutral-300">
+			    このゲームでは質問候補をこれ以上追加できません。
+			  </p>)}
 		      {(saveMutation.isError || questionSuggestionMutation.isError) && (
 			  <p className="text-sm text-red-600">
 			    記録できませんでした。通信状態を確認してもう一度試して。