diff --git a/backend/app/controllers/post_versions_controller.rb b/backend/app/controllers/post_versions_controller.rb
new file mode 100644
index 0000000..7b30b5a
--- /dev/null
+++ b/backend/app/controllers/post_versions_controller.rb
@@ -0,0 +1,29 @@
+class PostVersionsController < ApplicationController
+  def index
+    post_id = params[:post].presence
+    tag_id = params[:tag].presence
+    page = (params[:page].presence || 1).to_i
+    limit = (params[:limit].presence || 20).to_i
+
+    page = 1 if page < 1
+    limit = 1 if limit < 1
+
+    offset = (page - 1) * limit
+
+    tag_name = nil
+    if tag_id
+      tag_name = TagName.joins(:tag).find_by(tag: { id: tag_id })
+      return render json: [] unless tag_name
+    end
+
+    q = PostVersion
+    q = q.where(post_id:) if post_id
+    q = q.where("CONCAT(' ', tags, ' ') LIKE ?", "% #{ tag_name } %") if tag_name
+
+    versions = q.order(created_at: :desc, id: :desc)
+                .limit(limit)
+                .offset(offset)
+
+    render json: { versions:, count: q.count }
+  end
+end
diff --git a/backend/app/controllers/posts_controller.rb b/backend/app/controllers/posts_controller.rb
index fda77ed..c6e2d7d 100644
--- a/backend/app/controllers/posts_controller.rb
+++ b/backend/app/controllers/posts_controller.rb
@@ -204,7 +204,7 @@ class PostsController < ApplicationController
     pts = pts.where(post_id: id) if id.present?
     pts = pts.where(tag_id:) if tag_id.present?
     pts = pts.includes(:post, :created_user, :deleted_user,
-                       tag: { tag_name: :wiki_page })
+                       tag: [:materials, { tag_name: :wiki_page }])
 
     events = []
     pts.each do |pt|
diff --git a/backend/config/routes.rb b/backend/config/routes.rb
index fc56aa4..edd978f 100644
--- a/backend/config/routes.rb
+++ b/backend/config/routes.rb
@@ -49,6 +49,7 @@ Rails.application.routes.draw do
     collection do
       get :random
       get :changes
+      get :versions, to: 'post_versions#index'
     end
 
     member do
diff --git a/frontend/src/components/DraggableDroppableTagRow.tsx b/frontend/src/components/DraggableDroppableTagRow.tsx
index 6660f7e..55bc4d4 100644
--- a/frontend/src/components/DraggableDroppableTagRow.tsx
+++ b/frontend/src/components/DraggableDroppableTagRow.tsx
@@ -90,7 +90,9 @@ export default (({ tag, nestLevel, pathKey, parentTagId, suppressClickRef, sp }:
 	  className={cn ('rounded select-none', over && 'ring-2 ring-offset-2')}
 	  {...attributes}
 	  {...listeners}>
-	<motion.div layoutId={`tag-${ sp ? 'sp-' : '' }${ tag.id }`}>
+	<motion.div
+	    transition={{ layout: { duration: .2, ease: 'easeOut' } }}
+	    layoutId={`tag-${ sp ? 'sp-' : '' }${ tag.id }`}>
 	  <TagLink tag={tag} nestLevel={nestLevel}/>
 	</motion.div>
       </div>)
diff --git a/frontend/src/components/TagDetailSidebar.tsx b/frontend/src/components/TagDetailSidebar.tsx
index c02eca9..e195619 100644
--- a/frontend/src/components/TagDetailSidebar.tsx
+++ b/frontend/src/components/TagDetailSidebar.tsx
@@ -313,7 +313,9 @@ export default (({ post, sp }: Props) => {
 	  {CATEGORIES.map ((cat: Category) => ((tags[cat] ?? []).length > 0 || dragging) && (
 	      <div className="my-3" key={cat}>
 		<SubsectionTitle>
-		  <motion.div layoutId={`tag-${ sp ? 'sp-' : '' }${ cat }`}>
+		  <motion.div
+		      layoutId={`tag-${ sp ? 'sp-' : '' }${ cat }`}
+		      transition={{ layout: { duration: .2, ease: 'easeOut' } }}>
 		    {CATEGORY_NAMES[cat]}
 		  </motion.div>
 		</SubsectionTitle>
@@ -325,7 +327,9 @@ export default (({ post, sp }: Props) => {
 		</ul>
 	      </div>))}
 	  {post && (
-	      <motion.div layoutId={`post-info-${ sp }`}>
+	      <motion.div
+		  layoutId={`post-info-${ sp }`}
+		  transition={{ layout: { duration: .2, ease: 'easeOut' } }}>
 		<SectionTitle>情報</SectionTitle>
 		<ul>
 		  <li>Id.: {post.id}</li>
diff --git a/frontend/src/types.ts b/frontend/src/types.ts
index c453a10..57e2dd5 100644
--- a/frontend/src/types.ts
+++ b/frontend/src/types.ts
@@ -136,6 +136,21 @@ export type PostTagChange = {
     changeType: 'add' | 'remove'
     timestamp:  string }
 
+export type PostVersion = {
+    postId:                 number
+    versionNo:              number
+    eventType:              'create' | 'update' | 'discard' | 'restore'
+    title:                  string
+    url:                    string
+    thumbnail:              string
+    thumbnailBase:          string
+    tags:                   Tag[]
+    parent:                 Post | null
+    originalCreatedFrom:    string | null
+    originalCreatedBefore:  string | null
+    createdAt:              string
+    createdByUser:          { id: number; name: string | null } | null }
+
 export type SubMenuComponentItem = {
     component:  ReactNode
     visible:    boolean }