diff --git a/backend/app/models/gekanator_question.rb b/backend/app/models/gekanator_question.rb
index a4c838f..8f9b925 100644
--- a/backend/app/models/gekanator_question.rb
+++ b/backend/app/models/gekanator_question.rb
@@ -13,7 +13,10 @@ class GekanatorQuestion < ApplicationRecord
   validates :condition, presence: true
   validates :priority_weight,
             presence: true,
-            numericality: { greater_than: 0 }
+            numericality: {
+              greater_than: 0,
+              less_than_or_equal_to: 3
+            }
 
   scope :accepted, -> { where(status: 'accepted') }
 end
diff --git a/frontend/src/pages/GekanatorPage.tsx b/frontend/src/pages/GekanatorPage.tsx
index 7a42884..2eef5b6 100644
--- a/frontend/src/pages/GekanatorPage.tsx
+++ b/frontend/src/pages/GekanatorPage.tsx
@@ -125,7 +125,7 @@ const sourcePriorityOffset = (question: GekanatorQuestion): number => {
 
 
 const priorityWeightOffset = (question: GekanatorQuestion): number =>
-    (question.priorityWeight - 1) * -.8
+    (Math.min (3, Math.max (.2, question.priorityWeight)) - 1) * -.8
 
 
 const createGameSeed = (): string => {
@@ -447,16 +447,162 @@ const softenNextQuestionIds = ({
 }
 
 
+type ExclusiveConditionGroup =
+    | 'original-month'
+    | 'original-year'
+    | 'original-month-day'
+    | 'source'
+
+
+const exclusiveConditionGroupFor = (
+    condition:  GekanatorQuestion['condition'],
+): ExclusiveConditionGroup | null => {
+  switch (condition.type)
+  {
+  case 'original-month':
+    return 'original-month'
+  case 'original-year':
+    return 'original-year'
+  case 'original-month-day':
+    return 'original-month-day'
+  case 'source':
+    return 'source'
+  default:
+    return null
+  }
+}
+
+
+const sameConditionValue = (
+    left:   GekanatorQuestion['condition'],
+    right:  GekanatorQuestion['condition'],
+): boolean => {
+  if (left.type !== right.type)
+    return false
+
+  const valueKeyFor = (condition: GekanatorQuestion['condition']): string => {
+    switch (condition.type)
+    {
+    case 'tag':
+      return condition.key
+    case 'source':
+      return condition.host
+    case 'original-year':
+      return String (condition.year)
+    case 'original-month':
+      return String (condition.month)
+    case 'original-month-day':
+      return condition.monthDay
+    case 'title-length-greater-than':
+      return String (condition.length)
+    case 'title-has-ascii':
+      return ''
+    }
+  }
+
+  return valueKeyFor (left) === valueKeyFor (right)
+}
+
+
+const monthForCondition = (
+    condition:  GekanatorQuestion['condition'],
+): number | null => {
+  if (condition.type === 'original-month')
+    return condition.month
+
+  if (condition.type !== 'original-month-day')
+    return null
+
+  const month = Number (condition.monthDay.split ('-')[0])
+  return Number.isInteger (month) ? month : null
+}
+
+
+const isMonthCrossMatch = (
+    candidate:  GekanatorQuestion['condition'],
+    previous:   GekanatorQuestion['condition'],
+): boolean => {
+  const candidateMonth = monthForCondition (candidate)
+  const previousMonth = monthForCondition (previous)
+  if (candidateMonth === null || previousMonth === null)
+    return false
+
+  const sameType = candidate.type === previous.type
+  if (sameType)
+    return false
+
+  return candidateMonth === previousMonth
+}
+
+
+const isExclusiveContradiction = (
+    candidate:  GekanatorQuestion['condition'],
+    previous:   GekanatorQuestion['condition'],
+): boolean => {
+  const candidateGroup = exclusiveConditionGroupFor (candidate)
+  const previousGroup = exclusiveConditionGroupFor (previous)
+
+  if (candidateGroup !== null && candidateGroup === previousGroup)
+    return !(sameConditionValue (candidate, previous))
+
+  const candidateMonth = monthForCondition (candidate)
+  const previousMonth = monthForCondition (previous)
+  if (candidateMonth !== null && previousMonth !== null)
+    return candidateMonth !== previousMonth
+
+  return false
+}
+
+
+const contradictionPenaltyFor = ({
+    question,
+    answers,
+}: {
+    question:  GekanatorQuestion
+    answers:   GekanatorAnswerLog[]
+}): number => {
+  return answers.reduce ((sum, answer) => {
+    const previous = answer.questionCondition
+    if (!(previous))
+      return sum
+
+    switch (answer.answer)
+    {
+    case 'yes':
+      return sum + (isExclusiveContradiction (question.condition, previous) ? 100 : 0)
+    case 'partial':
+      return sum + (isExclusiveContradiction (question.condition, previous) ? 25 : 0)
+    case 'no':
+      return sum + (
+	  sameConditionValue (question.condition, previous)
+	      || isMonthCrossMatch (question.condition, previous)
+	    ? 40
+	    : 0)
+    case 'probably_no':
+      return sum + (
+	  sameConditionValue (question.condition, previous)
+	      || isMonthCrossMatch (question.condition, previous)
+	    ? 20
+	    : 0)
+    default:
+      return sum
+    }
+  }, 0)
+}
+
+
 const chooseQuestion = ({
     posts,
     questions,
     scores,
+    answers,
     askedIds,
     gameSeed,
 }: {
     posts:      Post[]
     questions:  GekanatorQuestion[]
     scores:     Map<number, number>
+    answers:    GekanatorAnswerLog[]
     askedIds:   Set<string>
     gameSeed:   string
 }): GekanatorQuestion | null => {
@@ -527,6 +673,7 @@ 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 contradictionPenalty = contradictionPenaltyFor ({ question, answers })
 	const sourceBonus = sourcePriorityOffset (question)
 	const priorityBonus = priorityWeightOffset (question)
 
@@ -535,6 +682,7 @@ const chooseQuestion = ({
 		     + unweightedSplitScore * 8
 		     + tagPenalty
 		     + narrowPenalty
+		     + contradictionPenalty
 		     + sourceBonus
 		     + priorityBonus,
 		 narrow: narrowPenalty > 0 }
@@ -666,11 +814,18 @@ const GekanatorPage: FC = () => {
 
   const { data: posts = [], isLoading, error } = useQuery ({
       queryKey: gekanatorKeys.posts (),
-      queryFn: fetchGekanatorPosts })
-  const { data: acceptedQuestions = [], isFetched: acceptedQuestionsFetched } = useQuery ({
+      queryFn: fetchGekanatorPosts,
+      refetchOnWindowFocus: false })
+  const {
+      data: acceptedQuestions = [],
+      isFetched: acceptedQuestionsFetched,
+      isLoading: acceptedQuestionsLoading,
+      error: acceptedQuestionsError
+  } = useQuery ({
       queryKey: gekanatorKeys.questions (),
       queryFn: fetchGekanatorQuestions,
-      select: questions => questions.map (restoreGekanatorQuestion) })
+      select: questions => questions.map (restoreGekanatorQuestion),
+      refetchOnWindowFocus: false })
 
   useEffect (() => {
     if (
@@ -793,6 +948,7 @@ const GekanatorPage: FC = () => {
       posts: questionPosts,
       questions: scoringQuestions,
       scores,
+      answers,
       askedIds,
       gameSeed })
   const answerPreviews = useMemo (
@@ -896,6 +1052,7 @@ const GekanatorPage: FC = () => {
 		posts: recoveredEligiblePosts,
 		questions: recoveredScoringQuestions,
 		scores: recoveredScores,
+		answers: nextAnswers,
 		askedIds: nextAskedIds,
 		gameSeed })))
     )
@@ -1170,6 +1327,7 @@ const GekanatorPage: FC = () => {
 	    : nonRejectedPosts,
 	questions: recovered.scoringQuestions,
 	scores: recovered.scores,
+	answers,
 	askedIds,
 	gameSeed })
 
@@ -1229,6 +1387,8 @@ const GekanatorPage: FC = () => {
       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!</>
 	: <>私は<ruby>洗澡鹿<rt>シーザオグカ</rt></ruby>．質問から投稿を何でも当ててみせるよ</>
+  const introLoading = isLoading || acceptedQuestionsLoading
+  const readyToStart = !(introLoading) && acceptedQuestionsFetched && posts.length > 0
 
   return (
       <MainArea className="bg-yellow-50 dark:bg-red-975">
@@ -1258,15 +1418,16 @@ const GekanatorPage: FC = () => {
 		  {dialogue}
 		</p>
 
-		{isLoading && (
+		{introLoading && (
 		    <p>
 		      {phase === 'intro'
 		       ? '投稿を読み込んでゐます...'
 		       : '前回のグカネータ状態を復元してゐます...'}
 		    </p>)}
-		{Boolean (error) && <p>投稿を読み込めませんでした．</p>}
+		{(Boolean (error) || Boolean (acceptedQuestionsError))
+		    && <p>グカネータの質問データを読み込めませんでした．</p>}
 
-		{phase === 'intro' && !(isLoading) && posts.length > 0 && (
+		{phase === 'intro' && readyToStart && (
 		    <button
 			type="button"
 			className="rounded bg-pink-600 px-4 py-2 font-bold text-white