人月カンパニー
A free idle game about growing a tiny contract software shop into a listed company, with Brooks's law from The Mythical Man-Month built into the rules. The developer left the implementation to Claude Code.
Official site ningetsu-company.jcat-aki.workers.dev, verified Nov 3, 2026. Linked from the developer's Zenn article; the game page links the same X account (@nextstack_lab) as the developer's Zenn profile.
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 人月カンパニー
人月カンパニー (Ningetsu Company; 人月 means “man-month”) is a free idle game in Japanese that runs in desktop and phone browsers. You start as a tiny contract software company and try to grow it all the way to a stock market listing: write quotes to win projects, write code, hire engineers, deliver, and spend the revenue on the next investment. Technical debt builds up and sets projects on fire, cutting development power to a quarter until the fire is put out, and now and then a large project is offered, such as a timesheet system for a lunar base, with a deadline and a penalty of 30% of the fee if you miss it. The screen is styled like a spreadsheet laid out on Excel graph paper. The developer built Brooks's law from The Mythical Man-Month into the rules: new hires contribute nothing until their training ends and slow the whole team by 5% each (up to 40%), and once the team grows past what it can coordinate (8 people, plus 6 for every project manager) communication efficiency falls with the square of the excess, never below 30%. Eight milestones, such as a company trip to Okinawa or a TV commercial, give permanent bonuses between investments. According to the developer's autoplay simulations, the ending takes about 25 minutes when you hire carefully and about 58 minutes if you ignore Brooks's law. A second part, ひとり開発者とAI (“a solo developer and AI”), was added on 17 Oct 2026: a four-week part in which you choose how much to hand to an AI and spot risky lines in diffs the AI has written; the game labels it a trial version, with later weeks still in development. The AI in that part is scripted game content. The developer, who works full time on weekdays, says they left the implementation to Claude Code and took the role of playing it and giving feedback.
How it was built
Partially verifiedThe developer's Zenn article says that, because they work full time on weekdays, they left the implementation to Claude Code and took the role of playing the game and saying what they thought. Each piece of feedback (for example that the game turned monotonous after hiring mid-level engineers, that moving buttons were distracting, that the ending felt unrewarding, or that hiring could slow a team down for a while as in The Mythical Man-Month) led Claude Code to add mechanics or rebalance; Brooks's law, the large projects and the sound effects all came in this way. No model is named and no share of AI-written code is given.
Written in TypeScript with Vite, with the game logic separated from the screen so that a Node autoplay script could imitate a reasonably careful player and print when each investment was reached. The first version reached the ending in about four minutes, so the developer made fees grow with the square root of trust instead of in proportion to it and raised the hiring-cost increase per person from 15% to 22%; milestones were added to fill four- to five-minute gaps after the fourth investment. Sound effects are synthesised with Web Audio, with fixes for phones in silent mode and for audio not resuming after switching apps. The game runs on Cloudflare Workers.
- Engine / framework
- None (TypeScript with Vite and Web Audio)
- Languages
- TypeScript
- Team size
- Not disclosed
- Development time
- Not disclosed
- Development cost
- Not disclosed
- AI-written code
- Not disclosed
“本業が平日フルタイムなので、実装はClaude Codeに任せ、自分は遊んで感想を伝える役に回りました。”Verification notes: AI use comes from the developer's Zenn article, published 4 Oct 2026 (Japan time) and updated 17 Oct 2026 with a note on Part 2; the article is tagged Claude Code, TypeScript and Vite. The release date is the article's publication date: it announces the finished game with the play link, and the game page gives no date. The tie between the article and the game rests on that link and on the X account @nextstack_lab, which both the Zenn profile and the game page link. Mechanics, numbers and play times come from the article; the game page says that all companies and people in it are fictional and labels Part 2 a trial version (体験版) whose later weeks are in development. The game's script makes no network requests apart from an X share link, an OFUSE tip link and Cloudflare's analytics beacon; the AI in Part 2 is scripted content, and no AI service runs during play. The Mythical Man-Month is a book on software project management and is used here as a theme, not as game IP. Japanese interface; no language setting found. Team size is not stated. The game was not played through.
Development history
The developer announces the game on Zenn as a free idle game for browsers and phones, explaining how Brooks's law was built into its rules.
DeveloperZenn (aki / jcat_aki)Part 2, ひとり開発者とAI, is released as a trial: a four-week part about choosing how much to hand to an AI and spotting risky lines in AI-written diffs. Part 1 gains the rule that trainees cause more accidents.
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 the browser; the game page links an OFUSE page for tips.
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 |
|---|---|---|---|
| 『人月の神話』のブルックスの法則を、放置ゲームの仕組みにしてみた Zenn (aki / jcat_aki) · Japanese | Devlog | Oct 4, 2026 | Nov 3, 2026 |
| 人月カンパニー (game page and script) aki (nextstack_lab) · Japanese | Official site | Not confirmed | Nov 3, 2026 |
| Official game page (language check) aki (nextstack_lab) | Official site | Not confirmed | Nov 3, 2026 |
