Nihonsia

Japanese history, walked instead of memorized.

A study game for 日本史 — the Japanese history section of the national university entrance exam. iOS. Launching August 2026.

the problem

A Japanese student sitting the Common Test has to hold several hundred dates, names and causes in their head. The standard tool for this is a stack of flashcards, and it works badly — history is a chain, and flashcards cut the chain into pieces. You end up with six hundred loose facts and no sense of what caused what.

The other thing flashcards fail at is showing up. Nobody opens a deck of cards on the train for one minute.

the idea

Put the chain back into a place. One island holds nine eras — you can see the whole of Japanese history at once, as landmarks on the ground. Tap an era and you walk into it; each chapter is a trail, and each stone on the trail is five questions, about a minute.

You move forward through time instead of shuffling cards, so the order is the thing you remember.

how it works

A stone is five questions, about a minute. Short enough to finish standing on a train.
Four answer formats. Multiple choice, type the year, true/false, and put events in order — the shapes the real exam uses.
Wrong answers come back. Spaced repetition schedules them, and the gap widens each time you get one right.
A mastery map. Dots fill in under each chapter as facts stick, so the thin parts are visible before the exam finds them.
A red sheet. The Japanese study ritual — a translucent red sheet laid over a page to hide the answers — rebuilt as a physical thing you drag with your thumb.
A reminder that doesn't nag. One local notification a day, skipped automatically on days you already studied.

numbers

eras

chapters

575

questions

21d

build time

built

Solo, in 21 days — first commit 17 July 2026, submitted for review on 7 August, 225 commits in between. SwiftUI and SpriteKit on the device, Cloudflare Workers and D1 behind it, RevenueCat for subscriptions, and Sign in with Apple so a new phone doesn't cost you your progress.

Every piece of art — the island, the landmarks, the seventeen chapter characters that hand out the questions — is generated and then hand-tuned into a single low-poly world.

SwiftUI SpriteKit Cloudflare Workers D1 RevenueCat Sign in with Apple

status

In App Store review · August 2026

Free: the first three stones. Pro unlocks all 17 chapters, review, the mastery map and the red sheet — ¥980 a month or ¥4,900 a year. No trial; the free part is the trial.