まもってわたる。
Free · play online in your browser, no download
Add up the numbers on the road to pay exactly, and a helper steps onto the last tile you tapped. A number-puzzle tower defence for one 40-second crossing, its code written almost entirely by Claude Code.
Official site vannangames.com, verified Nov 3, 2026. Play address linked from the game's page on VANNAN GAMES (vannangames.com), the developer's own site, which the developer's Zenn article links.
Where to play
Every platform this game is on. Links are checked against official sources; we never host or mirror games.
- Play free — official siteBrowserReleasedFree
Runs in a desktop or mobile browser. No download.
Browser (no download) · Mobile · Official link verified Nov 3, 2026.
About まもってわたる。
まもってわたる。 is a free number-puzzle tower defence game for the browser, in Japanese. At 8:05 in the morning Asuka has to cross the crossing from the developer's novel 四十秒の交差点, and you have 40 seconds to see Asuka safely across. Numbers sit in hopscotch rings on the road: pick a helper, then tap numbers until they add up to exactly its cost (going over is not accepted), and the helper stands on the last tile you tapped, so how you pay decides where it goes. Paying 8 as 3 + 5 or as 1 + 3 + 4 puts it in different places. Each helper guards only its own lane: the neighbourhood watch drives enemies off, the man with the yellow flag slows them, and the baker holds them up once with the smell of bread. Pigeons are the standard nuisance, bicycles are fast and joggers slow but tough. A 12-second red light is for setting up; when it turns green Asuka starts across and you keep adding helpers as you collect numbers. If an enemy reaches Asuka, Asuka is pushed back one tile, and if the crossing is not made in 40 seconds the day is lost. When Asuka makes it, the count of “today” goes up: helpers go home and forget, the numbers on the road carry over, and traffic gets heavier each day. The score is how many days you can keep it up, about a minute per day, with best days and repels saved in the browser and results shareable on X. It is the companion piece to みんなでわたる。 on the same site. Per the developer, kawaiy, the code is almost all written by Claude Code; the illustrations were generated with ChatGPT and the music with Suno. Plain HTML, CSS and JavaScript with no framework. Free in desktop and phone browsers.
How it was built
VerifiedIn a Zenn article (23 Aug 2026) about building the eight-game VANNAN GAMES site in 34 days, the developer lists the division of work as “Claude : コード、ドキュメント、シナリオの下書き、レビュー” (Claude: code, documents, scenario drafts, reviews) and writes “コードはほぼClaude Codeに書かせています。” (I have Claude Code write almost all of the code.) Check and generator scripts run from a Claude Code Stop hook after every agent reply and again on GitHub Actions. The developer notes that a balance simulator with automatic play gives the numbers, but whether a game is fun had to be judged by playing it.
- DeveloperA production note on the site (17 Sep 2026) opens: “このサイトは、コードを書く作業の大半をAIに頼んで作っています。” (This site is built by leaving most of the code writing to AI.) — VANNAN GAMES
Generated the illustrations; the game's page credits “イラスト：ChatGPTで生成” (illustrations generated with ChatGPT). The site's production notes include one on getting AI to draw a straight pedestrian crossing.
Plain HTML, CSS and JavaScript with no framework, served as static files from Tencent Cloud EdgeOne Pages; best records are saved in the browser's localStorage. Claude Code writes almost all of the code under checks run by a Stop hook; ChatGPT generates the illustrations and Suno the music. The game's page links a production note on shaping the rules with a simulation of skilled and unskilled play.
- Engine / framework
- None (vanilla JavaScript)
- Languages
- JavaScript
- Team size
- 1 (solo)Developer ReportedVANNAN GAMES
- Development time
- Not disclosed
- Development cost
- Not disclosed
- AI-written code
- Not disclosed
“コードはほぼClaude Codeに書かせています。”- Eight browser games in 34 days: Claude, ChatGPT and Suno, and what could not be handed off (Zenn, Japanese)
- Game page on VANNAN GAMES (Japanese)
Verification notes: AI use and the workflow come from the developer's Zenn article (23 Aug 2026, 02:03 JST), re-read through Zenn's API on 8 Nov 2026; it links vannangames.com. The article covers the whole site (eight games on 23 Aug 2026) and does not name this game, so the Claude Code statement is applied to each of its games. A production note on the site (17 Sep 2026) also says most of the code writing is left to AI. Rules, helpers, enemies, release date (公開日 2 Aug 2026, last updated 23 Aug 2026; the updates log calls it the site's sixth game) and credits (企画・開発：kawaiy; illustrations generated with ChatGPT, BGM with Suno) come from the game's page and the updates log, read on 8 Nov 2026. The site's operator page names kawaiy (個人) as the operator. The English title is our translation; there is no official English title. The game's script contains no AI service addresses; the site loads Google Analytics. The Japanese interface was observed (lang="ja"); no other language option was found. The game was not played.
Development history
Released on VANNAN GAMES as the site's sixth game.
The developer's Zenn article describes building the eight-game site with Claude Code writing almost all of the code.
DeveloperZenn (kawaiy)
Game performance
Each figure measures something different — concurrent players, owners, downloads and sales are never interchangeable and are never added together. Labels show where each number comes from.
Browser (official site)
Free in modern desktop and phone browsers, with no install or account; best records are saved in the browser and not sent anywhere, per the game's page. The site accepts optional support through OFUSE.
No public metrics recorded for this listing.
Not publicly available: Concurrent players (site), Monthly revenue, Gross revenue.
Sales & revenue (all platforms)
Browser game — there are no downloads to count.
Reviews & rankings
Not yet reviewed by our editors.
Not currently ranked.
Sources
| Source | Type | Published | Accessed |
|---|---|---|---|
| 34日でブラウザゲーム8本のサイトを立てた。Claude・ChatGPT・Sunoの分担と、丸投げできなかったもの Zenn (kawaiy) · Japanese | Devlog | Aug 23, 2026 | Nov 3, 2026 |
| まもってわたる。｜数字で守るタワーディフェンス｜VANNAN GAMES VANNAN GAMES · Japanese | Official site | Aug 2, 2026 | Nov 3, 2026 |
| 更新情報｜VANNAN GAMES VANNAN GAMES · Japanese | Official site | Not confirmed | Nov 3, 2026 |
| ルールを決めた8日後に、自分でそれを破った——AIへの指示を4つのレイヤーに分けた｜VANNAN GAMES 制作ノート VANNAN GAMES · Japanese | Devlog | Sep 17, 2026 | Nov 3, 2026 |
| VANNAN GAMESについて｜運営者情報 VANNAN GAMES · Japanese | Official site | Not confirmed | Nov 3, 2026 |
| Official game page (language check) VANNAN GAMES | Official site | Not confirmed | Nov 3, 2026 |
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