2026-06-12 02:08:59 +09:00
@@ -20,4 +20,91 @@ class GekanatorGamesController < ApplicationController
      render json: { errors: game.errors.full_messages }, status: :unprocessable_entity
    end
  end
+
+  def extra_questions
+    return head :not_found unless current_user&.admin?
+
+    game = GekanatorGame.find_by(id: params[:id])
+    return head :not_found unless game
+
+    asked_ids = Array(game.answers).filter_map { |answer|
+      answer['questionId'] || answer[:questionId]
+    }
+    existing_example_ids =
+        GekanatorQuestionExample.where(post_id: game.correct_post_id)
+                                .select(:gekanator_question_id)
+    questions =
+        GekanatorQuestion
+        .accepted
+        .where(kind: 'post_similarity', source: 'user_suggested')
+        .where.not(id: existing_example_ids)
+        .order(priority_weight: :desc, id: :asc)
+
+    render json: {
+      questions: questions.filter_map { |question|
+        json = extra_question_json(question)
+        next if asked_ids.include?(json[:id].to_s)
+        next if asked_ids.include?("post-similarity:#{ json[:id] }")
+
+        json
+      }.first(2)
+    }
+  end
+
+  def extra_question_answers
+    return head :not_found unless current_user&.admin?
+
+    game = GekanatorGame.find_by(id: params[:id])
+    return head :not_found unless game
+
+    answer_params = params.require(:answers)
+    if !answer_params.is_a?(Array)
+      return render_validation_error fields: { answers: ['配列で指定してください．'] }
+    end
+
+    answers = answer_params.map { |answer|
+      {
+        question_id: answer.require(:question_id),
+        answer: answer.require(:answer)
+      }
+    }
+    questions = GekanatorQuestion.where(id: answers.map { _1[:question_id] })
+    question_by_id = questions.index_by(&:id)
+    if questions.length != answers.length
+      return render_validation_error fields: { answers: ['質問が見つかりません．'] }
+    end
+    if questions.any? { |question| question.status != 'accepted' || question.kind != 'post_similarity' }
+      return render_validation_error fields: { answers: ['質問が不正です．'] }
+    end
+
+    ActiveRecord::Base.transaction do
+      answers.each do |item|
+        question = question_by_id[item[:question_id]]
+        example =
+            GekanatorQuestionExample.find_or_initialize_by(
+                gekanator_question: question,
+                post: game.correct_post,
+                user: current_user)
+        example.assign_attributes(
+            gekanator_game: game,
+            answer: item[:answer],
+            source: 'post_game_extra',
+            weight: 1.0)
+        example.save!
+      end
+    end
+
+    render json: { count: answers.length }, status: :created
+  end
+
+  private
+
+  def extra_question_json question
+    {
+      id: question.id,
+      text: question.text,
+      source: question.source,
+      priority_weight: question.priority_weight
+    }
+  end
 end
@@ -11,7 +11,14 @@ class GekanatorQuestionSuggestionsController < ApplicationController
        question_text: params.require(:question_text),
        answer: params.require(:answer))

-    if suggestion.save
+    if suggestion.valid?
+      ActiveRecord::Base.transaction do
+        suggestion.save!
+        Gekanator::QuestionSuggestionPromoter.call(
+            suggestion: suggestion,
+            user: current_user)
+      end
+
      render json: {
        id: suggestion.id,
        count: game.question_suggestions.count
@@ -2,7 +2,11 @@ class GekanatorQuestionsController < ApplicationController
  def index
    return head :not_found unless current_user&.admin?

-    questions = GekanatorQuestion.accepted.order(priority_weight: :desc, id: :asc)
+    questions =
+        GekanatorQuestion
+        .accepted
+        .includes(:gekanator_question_examples)
+        .order(priority_weight: :desc, id: :asc)

    render json: {
      questions: questions.map { |question| question_json(question) }
@@ -12,7 +16,7 @@ class GekanatorQuestionsController < ApplicationController
  private

  def question_json question
-    {
+    json = {
      id: question_id_for(question),
      text: question.text,
      kind: question.kind,
@@ -20,6 +24,10 @@ class GekanatorQuestionsController < ApplicationController
      source: question.source,
      priority_weight: question.priority_weight
    }
+    if question.kind == 'post_similarity'
+      json[:example_answers] = example_answers_json(question)
+    end
+    json
  end

  def question_id_for question
@@ -40,6 +48,8 @@ class GekanatorQuestionsController < ApplicationController
      "title:length-greater-than:#{ condition[:length] }"
    when 'title-has-ascii'
      'title:ascii'
+    when 'post-similarity'
+      "post-similarity:#{ question.id }"
    else
      "catalog:#{ question.id }"
    end
@@ -54,4 +64,20 @@ class GekanatorQuestionsController < ApplicationController

    json
  end
+
+  def example_answers_json question
+    question
+        .gekanator_question_examples
+        .group_by(&:post_id)
+        .transform_values { |examples| aggregate_answer(examples) }
+  end
+
+  def aggregate_answer examples
+    examples
+        .group_by(&:answer)
+        .map { |answer, grouped| [answer, grouped.sum(&:weight), grouped.max_by(&:updated_at)&.updated_at] }
+        .sort_by { |(_answer, weight, updated_at)| [-weight, -(updated_at&.to_f || 0)] }
+        .first
+        &.first
+  end
 end
@@ -5,6 +5,9 @@ class GekanatorGame < ApplicationRecord
  has_many :question_suggestions,
           class_name: 'GekanatorQuestionSuggestion',
           dependent: :delete_all
+  has_many :question_examples,
+           class_name: 'GekanatorQuestionExample',
+           dependent: :delete_all

  validates :answers, presence: true
  validates :question_count, numericality: { greater_than_or_equal_to: 0 }
@@ -1,10 +1,11 @@
 class GekanatorQuestion < ApplicationRecord
-  KINDS = ['tag', 'source', 'title', 'original_date'].freeze
+  KINDS = ['tag', 'source', 'title', 'original_date', 'post_similarity'].freeze
  SOURCES = ['user_suggested', 'ai_generated', 'admin_curated'].freeze
-  STATUSES = ['pending', 'accepted', 'rejected'].freeze
+  STATUSES = ['pending', 'accepted', 'rejected', 'disabled'].freeze

  belongs_to :gekanator_question_suggestion, optional: true
  belongs_to :created_by, class_name: 'User', optional: true
+  has_many :gekanator_question_examples, dependent: :delete_all

  validates :kind, presence: true, inclusion: { in: KINDS }
  validates :source, presence: true, inclusion: { in: SOURCES }
@@ -0,0 +1,17 @@
+class GekanatorQuestionExample < ApplicationRecord
+  ANSWERS = GekanatorQuestionSuggestion::ANSWERS
+  SOURCES = ['initial_suggestion', 'post_game_extra'].freeze
+
+  belongs_to :gekanator_question
+  belongs_to :post
+  belongs_to :user
+  belongs_to :gekanator_game, optional: true
+
+  validates :answer, presence: true, inclusion: { in: ANSWERS }
+  validates :source, presence: true, inclusion: { in: SOURCES }
+  validates :weight,
+            presence: true,
+            numericality: {
+              greater_than: 0
+            }
+end
@@ -21,6 +21,7 @@ class Post < ApplicationRecord
           foreign_key: :correct_post_id,
           dependent: :delete_all,
           inverse_of: :correct_post
+  has_many :gekanator_question_examples, dependent: :delete_all

  has_many :parent_post_implications,
           class_name: 'PostImplication',
@@ -0,0 +1,48 @@
+module Gekanator
+  class QuestionSuggestionPromoter
+    def self.call(...) = new(...).call
+
+    def initialize suggestion:, user:
+      @suggestion = suggestion
+      @user = user
+    end
+
+    def call
+      suggestion.with_lock do
+        return promoted_question if suggestion.processed?
+
+        question = GekanatorQuestion.create!(
+            text: suggestion.question_text,
+            kind: 'post_similarity',
+            source: 'user_suggested',
+            status: 'accepted',
+            priority_weight: 1.2,
+            condition: {
+              type: 'post-similarity',
+              postId: suggestion.gekanator_game.correct_post_id,
+              answer: suggestion.answer,
+              threshold: 0.65
+            },
+            gekanator_question_suggestion: suggestion,
+            created_by: user)
+        GekanatorQuestionExample.create!(
+            gekanator_question: question,
+            post: suggestion.gekanator_game.correct_post,
+            user: user,
+            gekanator_game: suggestion.gekanator_game,
+            answer: suggestion.answer,
+            source: 'initial_suggestion')
+        suggestion.update!(processed: true)
+        question
+      end
+    end
+
+    private
+
+    attr_reader :suggestion, :user
+
+    def promoted_question
+      suggestion.gekanator_questions.order(id: :desc).first
+    end
+  end
+end
@@ -64,7 +64,12 @@ Rails.application.routes.draw do
  end

  namespace :gekanator do
-    resources :games, only: [:create], controller: '/gekanator_games'
+    resources :games, only: [:create], controller: '/gekanator_games' do
+      member do
+        get :extra_questions
+        post :extra_question_answers
+      end
+    end
    resources :posts, only: [:index], controller: '/gekanator_posts'
    resources :questions, only: [:index], controller: '/gekanator_questions'
    resources :question_suggestions,
@@ -0,0 +1,19 @@
+class CreateGekanatorQuestionExamples < ActiveRecord::Migration[8.0]
+  def change
+    create_table :gekanator_question_examples do |t|
+      t.references :gekanator_question, null: false, foreign_key: true
+      t.references :post, null: false, foreign_key: true
+      t.references :user, null: false, foreign_key: true
+      t.references :gekanator_game, null: true, foreign_key: true
+      t.string :answer, null: false
+      t.string :source, null: false, default: 'post_game_extra'
+      t.float :weight, null: false, default: 1.0
+      t.timestamps
+    end
+
+    add_index :gekanator_question_examples,
+              [:gekanator_question_id, :post_id, :user_id],
+              unique: true,
+              name: 'idx_gekanator_question_examples_on_question_post_user'
+  end
+end
@@ -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_09_001000) do
+ActiveRecord::Schema[8.0].define(version: 2026_06_10_000000) 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
@@ -75,6 +75,23 @@ ActiveRecord::Schema[8.0].define(version: 2026_06_09_001000) do
    t.check_constraint "`question_count` >= 0", name: "chk_gekanator_games_question_count_nonnegative"
  end

+  create_table "gekanator_question_examples", charset: "utf8mb4", collation: "utf8mb4_0900_ai_ci", force: :cascade do |t|
+    t.bigint "gekanator_question_id", null: false
+    t.bigint "post_id", null: false
+    t.bigint "user_id", null: false
+    t.bigint "gekanator_game_id"
+    t.string "answer", null: false
+    t.string "source", default: "post_game_extra", null: false
+    t.float "weight", default: 1.0, null: false
+    t.datetime "created_at", null: false
+    t.datetime "updated_at", null: false
+    t.index ["gekanator_game_id"], name: "index_gekanator_question_examples_on_gekanator_game_id"
+    t.index ["gekanator_question_id", "post_id", "user_id"], name: "idx_gekanator_question_examples_on_question_post_user", unique: true
+    t.index ["gekanator_question_id"], name: "index_gekanator_question_examples_on_gekanator_question_id"
+    t.index ["post_id"], name: "index_gekanator_question_examples_on_post_id"
+    t.index ["user_id"], name: "index_gekanator_question_examples_on_user_id"
+  end
+
  create_table "gekanator_question_suggestions", charset: "utf8mb4", collation: "utf8mb4_0900_ai_ci", force: :cascade do |t|
    t.bigint "gekanator_game_id", null: false
    t.bigint "user_id", null: false
@@ -553,6 +570,10 @@ ActiveRecord::Schema[8.0].define(version: 2026_06_09_001000) do
  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_examples", "gekanator_games"
+  add_foreign_key "gekanator_question_examples", "gekanator_questions"
+  add_foreign_key "gekanator_question_examples", "posts"
+  add_foreign_key "gekanator_question_examples", "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"
@@ -21,6 +21,7 @@ export type GekanatorQuestionKind =
    | 'source'
    | 'title'
    | 'original_date'
+    | 'post_similarity'

 export type GekanatorQuestionSource =
    | 'default'
@@ -36,6 +37,18 @@ export type GekanatorQuestionCondition =
    | { type: 'original-month-day'; monthDay: string }
    | { type: 'title-length-greater-than'; length: number }
    | { type: 'title-has-ascii' }
+    | {
+	  type: 'post-similarity'
+	  postId: number
+	  answer: GekanatorAnswerValue
+	  threshold: number
+      }
+
+export type GekanatorExtraQuestion = {
+    id:              number
+    text:            string
+    source:          GekanatorQuestionSource
+    priorityWeight:  number }

 export type StoredGekanatorQuestion = {
    id:              string
@@ -43,7 +56,8 @@ export type StoredGekanatorQuestion = {
    kind:            GekanatorQuestionKind
    condition:       GekanatorQuestionCondition
    source?:         GekanatorQuestionSource
-    priorityWeight?: number }
+    priorityWeight?: number
+    exampleAnswers?: Record<`${ number }`, GekanatorAnswerValue> }

 export type GekanatorQuestion = {
    id:              string
@@ -52,8 +66,24 @@ export type GekanatorQuestion = {
    condition:       GekanatorQuestionCondition
    source:          GekanatorQuestionSource
    priorityWeight:  number
+    exampleAnswers?: Record<`${ number }`, GekanatorAnswerValue>
    test:            (post: Post) => boolean }

+
+const directExampleAnswerFor = (
+    question:  StoredGekanatorQuestion,
+    post:      Post,
+): GekanatorAnswerValue | null => {
+  const direct = question.exampleAnswers?.[String (post.id) as `${ number }`]
+  if (direct)
+    return direct
+
+  if (question.condition.type === 'post-similarity' && question.condition.postId === post.id)
+    return question.condition.answer
+
+  return null
+}
+
 const countBy = <T extends string | number> (values: T[]): Map<T, number> => {
  const counts = new Map<T, number> ()
  values.forEach (value => counts.set (value, (counts.get (value) ?? 0) + 1))
@@ -172,24 +202,59 @@ const questionableTag = (post: Post, key: string): boolean => {

 const questionMatches = (
    post:       Post,
-    condition:  GekanatorQuestionCondition,
+    question:   StoredGekanatorQuestion,
 ): boolean => {
-  switch (condition.type)
+  const directAnswer = directExampleAnswerFor (question, post)
+  if (directAnswer)
+    return question.condition.type === 'post-similarity'
+	? directAnswer === question.condition.answer
+	: directAnswer === 'yes'
+
+  switch (question.condition.type)
  {
  case 'tag':
-    return questionableTag (post, condition.key)
+    return questionableTag (post, question.condition.key)
  case 'source':
-    return hostOf (post) === condition.host
+    return hostOf (post) === question.condition.host
  case 'original-year':
-    return originalYearOf (post) === condition.year
+    return originalYearOf (post) === question.condition.year
  case 'original-month':
-    return originalMonthOf (post) === condition.month
+    return originalMonthOf (post) === question.condition.month
  case 'original-month-day':
-    return originalMonthDayOf (post) === condition.monthDay
+    return originalMonthDayOf (post) === question.condition.monthDay
  case 'title-length-greater-than':
-    return (post.title?.length ?? 0) > condition.length
+    return (post.title?.length ?? 0) > question.condition.length
  case 'title-has-ascii':
    return /[A-Za-z0-9]/.test (post.title ?? '')
+  case 'post-similarity':
+    return false
+  }
+}
+
+
+export const expectedAnswerForQuestion = (
+    question:  StoredGekanatorQuestion | GekanatorQuestion | undefined,
+    post:      Post | null,
+): GekanatorAnswerValue | null => {
+  if (!(question) || !(post))
+    return null
+
+  const directAnswer = directExampleAnswerFor (question, post)
+  if (directAnswer)
+    return directAnswer
+
+  switch (question.condition.type)
+  {
+  case 'tag':
+  case 'source':
+  case 'original-year':
+  case 'original-month':
+  case 'original-month-day':
+  case 'title-length-greater-than':
+  case 'title-has-ascii':
+    return questionMatches (post, question) ? 'yes' : 'no'
+  case 'post-similarity':
+    return null
  }
 }

@@ -200,7 +265,7 @@ export const restoreGekanatorQuestion = (
  ...question,
  source: question.source ?? 'default',
  priorityWeight: question.priorityWeight ?? 1,
-  test: (post: Post) => questionMatches (post, question.condition) })
+  test: (post: Post) => questionMatches (post, question) })


 export const storeGekanatorQuestion = (
@@ -211,7 +276,8 @@ export const storeGekanatorQuestion = (
  kind: question.kind,
  condition: question.condition,
  source: question.source,
-  priorityWeight: question.priorityWeight })
+  priorityWeight: question.priorityWeight,
+  exampleAnswers: question.exampleAnswers })


 export const fetchGekanatorPosts = async (): Promise<Post[]> => {
@@ -226,6 +292,15 @@ export const fetchGekanatorQuestions = async (): Promise<StoredGekanatorQuestion
 }


+export const fetchGekanatorExtraQuestions = async (
+    gameId: number,
+): Promise<GekanatorExtraQuestion[]> => {
+  const data = await apiGet<{ questions: GekanatorExtraQuestion[] }> (
+      `/gekanator/games/${ gameId }/extra_questions`)
+  return data.questions
+}
+
+
 export const buildGekanatorQuestions = (posts: Post[]): GekanatorQuestion[] => {
  const tagCounts = countBy (posts.flatMap (post =>
      post.tags
@@ -393,3 +468,16 @@ export const saveGekanatorQuestionSuggestion = async ({
 	gekanator_game_id: gekanatorGameId,
 	question_text: questionText,
 	answer })
+
+
+export const saveGekanatorExtraQuestionAnswers = async ({
+    gameId,
+    answers,
+}: {
+    gameId:   number
+    answers:  { questionId: number; answer: GekanatorAnswerValue }[]
+}) =>
+    await apiPost (`/gekanator/games/${ gameId }/extra_question_answers`, {
+	answers: answers.map (item => ({
+	    question_id: item.questionId,
+	    answer: item.answer })) })
@@ -11,7 +11,9 @@ export const postsKeys = {
 export const gekanatorKeys = {
    root:      ['gekanator'] as const,
    posts:     () => ['gekanator', 'posts'] as const,
-    questions: () => ['gekanator', 'questions'] as const }
+    questions: () => ['gekanator', 'questions'] as const,
+    extraQuestions: (gameId: number) =>
+		       ['gekanator', 'games', gameId, 'extra-questions'] as const }

 export const tagsKeys = {
    root:         ['tags'] as const,
@@ -1,4 +1,4 @@
-import { useMutation, useQuery } from '@tanstack/react-query'
+import { useMutation, useQuery, useQueryClient } from '@tanstack/react-query'
 import { useEffect, useMemo, useState } from 'react'
 import { Helmet } from 'react-helmet-async'

@@ -6,9 +6,12 @@ import PrefetchLink from '@/components/PrefetchLink'
 import MainArea from '@/components/layout/MainArea'
 import { SITE_TITLE } from '@/config'
 import { buildGekanatorQuestions,
+	 expectedAnswerForQuestion,
+	 fetchGekanatorExtraQuestions,
 	 fetchGekanatorQuestions,
 	 fetchGekanatorPosts,
 	 restoreGekanatorQuestion,
+	 saveGekanatorExtraQuestionAnswers,
 	 saveGekanatorGame,
 	 saveGekanatorQuestionSuggestion,
 	 storeGekanatorQuestion } from '@/lib/gekanator'
@@ -19,6 +22,7 @@ import type { FC } from 'react'

 import type { GekanatorAnswerLog,
 	      GekanatorAnswerValue,
+	      GekanatorExtraQuestion,
 	      GekanatorQuestion,
 	      StoredGekanatorQuestion } from '@/lib/gekanator'
 import type { Post } from '@/types'
@@ -31,6 +35,7 @@ type Phase =
    | 'end'
    | 'review'
    | 'question_suggestion'
+    | 'extra_questions'
    | 'learned'

 type AnswerOption = {
@@ -87,7 +92,10 @@ type StoredGekanatorGame = {
    gameSeed?:                   string
    questionSuggestion:          string
    questionSuggestionAnswer:    GekanatorAnswerValue
-    questionSuggestionCount?:    number }
+    questionSuggestionCount?:    number
+    extraQuestions?:             GekanatorExtraQuestion[]
+    extraQuestionAnswers?:       Record<string, GekanatorAnswerValue>
+    extraQuestionState?:         'idle' | 'loading' | 'ready' | 'empty' | 'saved' }

 const answerOptions: AnswerOption[] = [
    { label: 'はい', value: 'yes' },
@@ -219,6 +227,16 @@ const loadStoredGame = (): StoredGekanatorGame | null => {
 const isStoredPhase = (phase: Phase): boolean => phase !== 'intro'


+const resettableExtraQuestionState = (): {
+    extraQuestions:        GekanatorExtraQuestion[]
+    extraQuestionAnswers:  Record<string, GekanatorAnswerValue>
+    extraQuestionState:    'idle'
+} => ({
+  extraQuestions: [],
+  extraQuestionAnswers: { },
+  extraQuestionState: 'idle' })
+
+
 const deltaFor = (matched: boolean, answer: GekanatorAnswerValue): number => {
  switch (answer)
  {
@@ -236,6 +254,55 @@ const deltaFor = (matched: boolean, answer: GekanatorAnswerValue): number => {
 }


+const answerScalarFor = (
+    answer:  GekanatorAnswerValue | null,
+): number | null => {
+  switch (answer)
+  {
+  case 'yes':
+    return 1
+  case 'partial':
+    return .5
+  case 'probably_no':
+    return -.5
+  case 'no':
+    return -1
+  case 'unknown':
+  case null:
+    return null
+  }
+}
+
+
+const deltaForExpectedAnswer = (
+    expected:  GekanatorAnswerValue | null,
+    answer:    GekanatorAnswerValue,
+): number => {
+  if (answer === 'unknown' || expected === null || expected === 'unknown')
+    return 0
+
+  if (expected === 'yes' || expected === 'no')
+    return deltaFor (expected === 'yes', answer)
+
+  const expectedScalar = answerScalarFor (expected)
+  const answerScalar = answerScalarFor (answer)
+  if (expectedScalar === null || answerScalar === null)
+    return 0
+
+  const distance = Math.abs (expectedScalar - answerScalar)
+  if (distance >= 2)
+    return -4
+  if (distance >= 1.5)
+    return -2
+  if (distance >= 1)
+    return 0
+  if (distance >= .5)
+    return 2
+
+  return 4
+}
+
+
 const answerWeightFor = (
    questionId:           string,
    softenedQuestionIds:  Set<string>,
@@ -277,10 +344,11 @@ const recalculateScores = ({

    const weight = answerWeightFor (answer.questionId, softenedQuestionIds)
    posts.forEach (post => {
+      const expected = expectedAnswerForQuestion (question, post)
      nextScores.set (
 	  post.id,
 	  (nextScores.get (post.id) ?? 0)
-	      + deltaFor (question.test (post), answer.answer) * weight)
+	      + deltaForExpectedAnswer (expected, answer.answer) * weight)
    })
  })

@@ -318,9 +386,10 @@ const candidatePostsFor = ({
      switch (answer.answer)
      {
      case 'yes':
-	return question.test (post)
-      case 'no':
-	return !(question.test (post))
+      case 'no': {
+	const expected = expectedAnswerForQuestion (question, post)
+	return expected === null || expected === 'unknown' || expected === answer.answer
+      }
      default:
 	return true
      }
@@ -378,20 +447,19 @@ const previewAnswer = ({
    answer:    GekanatorAnswerValue
 }): AnswerPreview => {
  const hardFilteredPosts =
-      answer === 'yes'
-	? posts.filter (post => question.test (post))
-	: answer === 'no'
-	  ? posts.filter (post => !(question.test (post)))
-	  : posts
+      answer === 'unknown'
+	? posts
+	: posts.filter (post => expectedAnswerForQuestion (question, post) === answer)
  const nextPosts =
-      (answer === 'yes' || answer === 'no') && hardFilteredPosts.length > 0
+      answer !== 'unknown' && hardFilteredPosts.length > 0
 	? hardFilteredPosts
 	: posts
  const nextScores = new Map (scores)
  nextPosts.forEach (post => {
+    const expected = expectedAnswerForQuestion (question, post)
    nextScores.set (
 	post.id,
-	(nextScores.get (post.id) ?? 0) + deltaFor (question.test (post), answer))
+	(nextScores.get (post.id) ?? 0) + deltaForExpectedAnswer (expected, answer))
  })

  const confidences = confidencesFor (nextPosts, nextScores)
@@ -497,6 +565,8 @@ const sameConditionValue = (
      return String (condition.length)
    case 'title-has-ascii':
      return ''
+    case 'post-similarity':
+      return `${ condition.postId }:${ condition.answer }:${ condition.threshold }`
    }
  }

@@ -757,16 +827,13 @@ const PostMiniCard: FC<{ post: Post }> = ({ post }) => (
 const expectedAnswerFor = (
    question:     GekanatorQuestion | undefined,
    correctPost:  Post | null,
-): GekanatorAnswerValue | null => {
-  if (!(question) || !(correctPost))
-    return null
-
-  return question.test (correctPost) ? 'yes' : 'no'
-}
+): GekanatorAnswerValue | null =>
+    expectedAnswerForQuestion (question, correctPost)


 const GekanatorPage: FC = () => {
  const storedGame = useMemo (loadStoredGame, [])
+  const queryClient = useQueryClient ()
  const [gameSeed, setGameSeed] = useState (
      storedGame?.gameSeed ?? createGameSeed ())
  const [phase, setPhase] = useState<Phase> (storedGame?.phase ?? 'intro')
@@ -810,6 +877,14 @@ const GekanatorPage: FC = () => {
      useState<GekanatorAnswerValue> (storedGame?.questionSuggestionAnswer ?? 'yes')
  const [questionSuggestionCount, setQuestionSuggestionCount] = useState (
      storedGame?.questionSuggestionCount ?? 0)
+  const [extraQuestions, setExtraQuestions] = useState<GekanatorExtraQuestion[]> (
+      storedGame?.extraQuestions ?? [])
+  const [extraQuestionAnswers, setExtraQuestionAnswers] =
+      useState<Record<string, GekanatorAnswerValue>> (
+	  storedGame?.extraQuestionAnswers ?? { })
+  const [extraQuestionState, setExtraQuestionState] = useState<
+      'idle' | 'loading' | 'ready' | 'empty' | 'saved'
+  > (storedGame?.extraQuestionState ?? 'idle')
  const [history, setHistory] = useState<GameSnapshot[]> ([])

  const { data: posts = [], isLoading, error } = useQuery ({
@@ -876,7 +951,10 @@ const GekanatorPage: FC = () => {
 	gameSeed,
 	questionSuggestion,
 	questionSuggestionAnswer,
-	questionSuggestionCount }
+	questionSuggestionCount,
+	extraQuestions,
+	extraQuestionAnswers,
+	extraQuestionState }

    try
    {
@@ -908,7 +986,10 @@ const GekanatorPage: FC = () => {
      gameSeed,
      questionSuggestion,
      questionSuggestionAnswer,
-      questionSuggestionCount])
+      questionSuggestionCount,
+      extraQuestions,
+      extraQuestionAnswers,
+      extraQuestionState])

  const eligiblePosts = useMemo (
      () => candidatePostsFor ({
@@ -985,10 +1066,25 @@ const GekanatorPage: FC = () => {
 	setQuestionSuggestion ('')
 	setQuestionSuggestionAnswer ('yes')
      }})
+  const extraQuestionAnswersMutation = useMutation ({
+      mutationFn: saveGekanatorExtraQuestionAnswers,
+      onSuccess: () => {
+	setExtraQuestionState ('saved')
+	setPhase ('learned')
+      }})
+
+  const resetExtraQuestionState = () => {
+    const next = resettableExtraQuestionState ()
+    setExtraQuestions (next.extraQuestions)
+    setExtraQuestionAnswers (next.extraQuestionAnswers)
+    setExtraQuestionState (next.extraQuestionState)
+    extraQuestionAnswersMutation.reset ()
+  }

  const reset = () => {
    clearStoredGame ()
    saveMutation.reset ()
+    questionSuggestionMutation.reset ()
    setPhase ('intro')
    setScores (new Map ())
    setAnswers ([])
@@ -1010,6 +1106,7 @@ const GekanatorPage: FC = () => {
    setQuestionSuggestion ('')
    setQuestionSuggestionAnswer ('yes')
    setQuestionSuggestionCount (0)
+    resetExtraQuestionState ()
    setHistory ([])
  }

@@ -1188,6 +1285,7 @@ const GekanatorPage: FC = () => {

    saveMutation.reset ()
    questionSuggestionMutation.reset ()
+    resetExtraQuestionState ()
    setSaved (false)
    setSavedGameId (null)
    setReviewGuessedPostId (guessedPostId)
@@ -1203,6 +1301,7 @@ const GekanatorPage: FC = () => {

    saveMutation.reset ()
    questionSuggestionMutation.reset ()
+    resetExtraQuestionState ()
    setSaved (false)
    setSavedGameId (null)
    setSelectingCorrectPost (false)
@@ -1236,6 +1335,7 @@ const GekanatorPage: FC = () => {
  }

  const saveAndLearn = () => {
+    resetExtraQuestionState ()
    saveReviewedResult (() => setPhase ('learned'))
  }

@@ -1344,6 +1444,7 @@ const GekanatorPage: FC = () => {
  const correctAnswerAt = (index: number, value: GekanatorAnswerValue) => {
    setSaved (false)
    setSavedGameId (null)
+    resetExtraQuestionState ()
    setAnswers (answers.map ((answer, i) =>
 	i === index ? { ...answer, answer: value } : answer))
  }
@@ -1353,6 +1454,7 @@ const GekanatorPage: FC = () => {
      {
 	setSaved (false)
 	setSavedGameId (null)
+	resetExtraQuestionState ()
 	setReviewCorrectPostId (post.id)
 	setSelectingCorrectPost (false)
 	setSearch ('')
@@ -1383,6 +1485,60 @@ const GekanatorPage: FC = () => {
      })
      .slice (0, 20)

+  const loadExtraQuestions = async (gameId: number) => {
+    extraQuestionAnswersMutation.reset ()
+    setExtraQuestionState ('loading')
+    setExtraQuestions ([])
+    setExtraQuestionAnswers ({ })
+    setPhase ('extra_questions')
+
+    try
+    {
+      const questions = await queryClient.fetchQuery ({
+	  queryKey: gekanatorKeys.extraQuestions (gameId),
+	  queryFn: () => fetchGekanatorExtraQuestions (gameId) })
+      setExtraQuestions (questions)
+      setExtraQuestionState (questions.length > 0 ? 'ready' : 'empty')
+    }
+    catch
+    {
+      setExtraQuestionState ('empty')
+    }
+  }
+
+  const startExtraQuestions = () => {
+    if (reviewCorrectPostId === null || saveMutation.isPending)
+      return
+
+    saveReviewedResult (gameId => {
+      void loadExtraQuestions (gameId)
+    })
+  }
+
+  const answerExtraQuestion = (
+      questionId:  number,
+      value:       GekanatorAnswerValue,
+  ) => {
+    setExtraQuestionAnswers ({
+	...extraQuestionAnswers,
+	[String (questionId)]: value })
+  }
+
+  const saveExtraQuestions = () => {
+    if (
+	savedGameId === null
+	|| extraQuestionAnswersMutation.isPending
+	|| extraQuestions.some (question => !(extraQuestionAnswers[String (question.id)]))
+    )
+      return
+
+    extraQuestionAnswersMutation.mutate ({
+	gameId: savedGameId,
+	answers: extraQuestions.map (question => ({
+	    questionId: question.id,
+	    answer: extraQuestionAnswers[String (question.id)] })) })
+  }
+
  const dialogue =
      phase === 'learned' && resultWon
 	? <>グカカカカwwwww  <ruby>洗澡鹿<rt>シーザオグカ</rt></ruby>は何でもお見通し!</>
@@ -1650,6 +1806,18 @@ const GekanatorPage: FC = () => {
 			    onClick={() => setPhase ('question_suggestion')}>
 			  質問を追加
 			</button>
+			<button
+			    type="button"
+			    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
+				      || saveMutation.isPending
+				      || extraQuestionState === 'loading'
+				      || extraQuestionAnswersMutation.isPending}
+			    onClick={startExtraQuestions}>
+			  追加で質問に答へる
+			</button>
 		      </div>
 		    </div>)}

@@ -1843,9 +2011,81 @@ const GekanatorPage: FC = () => {
 			  </p>)}
 		    </div>)}

+		{phase === 'extra_questions' && (
+		    <div className="space-y-4">
+		      <div>
+			<p className="text-sm text-neutral-500">追加学習</p>
+			<p className="text-xl font-bold">追加で 2 問まで答へてください。</p>
+		      </div>
+
+		      {extraQuestionState === 'loading' && (
+			  <p>追加質問を読み込んでゐます...</p>)}
+
+		      {extraQuestionState === 'empty' && (
+			  <p>追加で学習できる質問はありませんでした。</p>)}
+
+		      {extraQuestionState === 'ready' && (
+			  <div className="space-y-3">
+			    {extraQuestions.map ((question, index) => (
+				<div
+				    key={question.id}
+				    className="rounded border border-yellow-100 p-3
+					       dark:border-red-900">
+				  <div className="text-sm text-neutral-600 dark:text-neutral-300">
+				    追加質問 {index + 1}
+				  </div>
+				  <div className="font-bold">{question.text}</div>
+				  <div className="mt-3 flex flex-wrap gap-2">
+				    {answerOptions.map (option => (
+					<button
+					    key={option.value}
+					    type="button"
+					    className={cn (
+						'rounded border px-3 py-2',
+						extraQuestionAnswers[String (question.id)] === option.value
+						  ? 'border-pink-600 bg-pink-600 text-white'
+						  : 'border-yellow-300 hover:bg-yellow-100 dark:border-red-700 dark:hover:bg-red-900')}
+					    onClick={() => answerExtraQuestion (question.id, option.value)}>
+					  {option.label}
+					</button>))}
+				  </div>
+				</div>))}
+			  </div>)}
+
+		      {extraQuestionAnswersMutation.isError && (
+			  <p className="text-sm text-red-600">
+			    学習内容を保存できませんでした。通信状態を確認してもう一度試して。
+			  </p>)}
+
+		      <div className="flex flex-wrap gap-2">
+			<button
+			    type="button"
+			    className="rounded border border-neutral-300 px-4 py-2
+				       hover:bg-neutral-100 dark:border-neutral-700
+				       dark:hover:bg-red-900"
+			    disabled={extraQuestionAnswersMutation.isPending}
+			    onClick={() => setPhase ('end')}>
+			  戻る
+			</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={
+			      extraQuestionState !== 'ready'
+			      || extraQuestionAnswersMutation.isPending
+			      || extraQuestions.some (
+				  question => !(extraQuestionAnswers[String (question.id)]))
+			    }
+			    onClick={saveExtraQuestions}>
+			  学習する
+			</button>
+		      </div>
+		    </div>)}
+
 		{phase === 'learned' && (
 		    <div className="space-y-3">
-		      <p>覚えたよ．次はもっと見通す．</p>
+		      <p>{extraQuestionState === 'saved' ? '学習しました。' : '覚えたよ．次はもっと見通す．'}</p>
 		      <button
 			  type="button"
 			  className="rounded bg-pink-600 px-4 py-2 font-bold text-white