diff --git a/adev-ja/src/content/events/v21.en.md b/adev-ja/src/content/events/v21.en.md
new file mode 100644
index 0000000000..d26d5ce36c
--- /dev/null
+++ b/adev-ja/src/content/events/v21.en.md
@@ -0,0 +1,37 @@
+![A retro 8-bit, pixel art style graphic announcing the upcoming release of Angular v21. The large, gradient 'v21' text dominates the frame. Next to it, in smaller text, are the words 'The Adventure Begins' and the release date '11-20-2025' inside a pink pixelated box. The Angular logo is in the bottom right corner.](assets/images/v21-event/angular-v21-hero.jpg 'Angular v21 Hero Image')
+
+# Angular v21: The Adventure Begins
+
+## Release Blog
+
+**Angular v21 is live**: check out the [v21 release blog](http://goo.gle/angular-v21-blog) to learn about all of the amazing new features coming your way.
+
+## Experience the v21 Release
+
+Explore the Angular v21 release with this interactive game world. Curious how we made it? Click the `Show Code` button below to view the source code for this Angular app.
+
+<docs-code preview hideCode header="v21 Game World" path="adev/src/content/examples/v21-game-world/src/app/app.ts" />
+
+## Angular v21 Developer Event [Full Version]
+
+Angular v21 is being delivered to you as a brand new release adventure. With modern AI tooling, performance updates and more, Angular v21 delivers fantastic new features to improve your developer experience. Whether you’re creating AI-powered apps or scalable enterprise applications, there has never been a better time to build with Angular.
+
+🔥 What's coming in v21
+
+- New Angular MCP Server tools to improve AI-powered workflows and code generation
+- Your first look at Signal Forms, our new streamlined, signal-based approach to forms in Angular
+- Exciting new details about the Angular Aria package
+
+<div style="display: block; width: 80%; margin: 0 auto; margin-top: 20px;">
+  <iframe
+    credentialless
+    width="560"
+    height="315"
+    src="https://www.youtube.com/embed/DDAHORVzQ5g?si=B9Uv5vXzIKJfcLGr"
+    title="YouTube video player"
+    frameborder="0"
+    allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture; web-share"
+    referrerpolicy="strict-origin-when-cross-origin"
+    allowfullscreen
+  ></iframe>
+</div>
diff --git a/adev-ja/src/content/events/v21.md b/adev-ja/src/content/events/v21.md
index d26d5ce36c..8eb4396ce8 100644
--- a/adev-ja/src/content/events/v21.md
+++ b/adev-ja/src/content/events/v21.md
@@ -1,26 +1,26 @@
-![A retro 8-bit, pixel art style graphic announcing the upcoming release of Angular v21. The large, gradient 'v21' text dominates the frame. Next to it, in smaller text, are the words 'The Adventure Begins' and the release date '11-20-2025' inside a pink pixelated box. The Angular logo is in the bottom right corner.](assets/images/v21-event/angular-v21-hero.jpg 'Angular v21 Hero Image')
+![Angular v21の今後のリリースを告知する、レトロな8ビットのピクセルアートスタイルのグラフィック。大きなグラデーションの「v21」テキストがフレームを占めています。その隣には、小さなテキストで「The Adventure Begins」という言葉と、ピンク色のピクセル化されたボックス内にリリース日「11-20-2025」が記載されています。Angularのロゴは右下隅にあります。](assets/images/v21-event/angular-v21-hero.jpg 'Angular v21ヒーロー画像')
 
-# Angular v21: The Adventure Begins
+# Angular v21: 冒険の始まり
 
-## Release Blog
+## リリースブログ {#release-blog}
 
-**Angular v21 is live**: check out the [v21 release blog](http://goo.gle/angular-v21-blog) to learn about all of the amazing new features coming your way.
+**Angular v21がリリースされました**: [v21リリースブログ](http://goo.gle/angular-v21-blog)で、みなさんに提供されるすばらしい新機能のすべてをご確認ください。
 
-## Experience the v21 Release
+## v21リリースを体験する {#experience-the-v21-release}
 
-Explore the Angular v21 release with this interactive game world. Curious how we made it? Click the `Show Code` button below to view the source code for this Angular app.
+このインタラクティブなゲームの世界でAngular v21リリースを体験してください。どのように作られたか気になりますか？下の`Show Code`ボタンをクリックして、このAngularアプリケーションのソースコードをご覧ください。
 
 <docs-code preview hideCode header="v21 Game World" path="adev/src/content/examples/v21-game-world/src/app/app.ts" />
 
-## Angular v21 Developer Event [Full Version]
+## Angular v21開発者イベント [フルバージョン] {#angular-v21-developer-event-full-version}
 
-Angular v21 is being delivered to you as a brand new release adventure. With modern AI tooling, performance updates and more, Angular v21 delivers fantastic new features to improve your developer experience. Whether you’re creating AI-powered apps or scalable enterprise applications, there has never been a better time to build with Angular.
+Angular v21は、まったく新しいリリース体験としてお届けします。最新のAIツール、パフォーマンスアップデートなどにより、Angular v21は開発者体験を向上させるすばらしい新機能を提供します。AIを活用したアプリケーションやスケーラブルなエンタープライズアプリケーションを作成する場合でも、今ほどAngularで構築するのに最適な時期はありません。
 
-🔥 What's coming in v21
+🔥 v21の新機能
 
-- New Angular MCP Server tools to improve AI-powered workflows and code generation
-- Your first look at Signal Forms, our new streamlined, signal-based approach to forms in Angular
-- Exciting new details about the Angular Aria package
+- AIを活用したワークフローとコード生成を改善するための新しいAngular MCP Serverツール
+- Angularのフォームに対する、新しい合理化されたシグナルベースのアプローチであるシグナルフォームを初公開
+- Angular Ariaパッケージに関する注目の新情報
 
 <div style="display: block; width: 80%; margin: 0 auto; margin-top: 20px;">
   <iframe
@@ -28,7 +28,7 @@ Angular v21 is being delivered to you as a brand new release adventure. With mod
     width="560"
     height="315"
     src="https://www.youtube.com/embed/DDAHORVzQ5g?si=B9Uv5vXzIKJfcLGr"
-    title="YouTube video player"
+    title="YouTube動画プレイヤー"
     frameborder="0"
     allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture; web-share"
     referrerpolicy="strict-origin-when-cross-origin"