About

日本語版

Koshin Studio is a place for taking on anything, alone.
Make, try, write. Games, a quiz app and more, with records of how they were made and verified.

What you can do here

• English hub — games, tools and development logs in English
• Sushi Stack, Negaeri Shogi, Stop at exactly 10 seconds! — free browser games
• Hardcore Anime Type Diagnosis — an anime quiz with 64 types and 6 axes
• Gacha calculators — rate and pity calculators

How I work

Mostly alone, running things on my own machine as I go. Because I do everything from design to art to sound, I can fix what needs fixing on the spot.

For balance, I always prepare a way to measure. For a game, I let it play itself hundreds of times and look at where it gets stuck in numbers. It is much faster and more reliable than tweaking by feel three times and checking. The process is in a development log.

My feeling was right.
But the cause was not where I thought.

No install and no sign-up. It starts right away when you open it in a browser. That is the one thing I try not to break.

About the operator

Koshin Studio is run by Koshin (a nickname), alone. I work as a web engineer and an app engineer, and I make all sorts of things. I make and publish browser games, a quiz, and iPhone apps (such as Toreca Dash, available on the App Store). This site carries introductions to what I made, numbers I measured while making it, and records of bugs and how I fixed them.

The numbers in articles are ones I checked against my own app’s logs, data and source code, or official pages. What I could not confirm, I say I could not confirm. For feedback, corrections, interviews or work enquiries, please use the contact section below.

How the articles are written, and corrections

The articles in the development logs are written from real commits (work records) and measured numbers. I follow three rules.

• I write where the numbers come from. At the end of an article I say which record it was written from and when it was measured.
• I write “not verified” when I have not verified. Causes I never found and things I did not confirm on a real device are written as they are.
• I fix mistakes, and say I fixed them. When I learn something later, I add it to the article and change the update date (for example, the conger eel article got an addendum with the numbers after sizes changed).

If you notice a mistake in an article, please tell me using the contact below.

Tools I use

• Languages: JavaScript (the main one: games and the site), Python (fonts, image conversion, statistics tools), Swift (iOS apps), plain HTML and CSS written by hand.
• Games: Matter.js for physics, Canvas 2D for drawing every frame instead of using images, Web Audio for synthesized sound.
• The site: GSAP and ScrollTrigger, Lenis, and SVG (I even drew the logo letters myself).
• Hosting: Cloudflare Pages, Workers and D1 for this site and the ranking server, and Firebase for app backends.
• Tooling: Git and GitHub, Playwright (to let games play themselves and to walk the whole site), fontTools, Pillow and Xcode.

I add a framework only when I need it. This site added GSAP only when it came to thickening the motion. It does not connect to outside CDNs; everything it uses is on my own server, which is fast and unaffected when others go down. Fonts are trimmed to the characters needed instead of pasting a stock font.

Contact

Corrections, impressions and questions are welcome. I may not be able to reply to everything, but I read them.

How personal information and quiz answers are handled is written on the privacy page. This is the English version of the Japanese page.