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Build it to understand it.

Hands-on courses that run entirely in your browser. No install, no server, no build step — just you, a language, and a blank canvas.

Tetris in Java

12 steps. Pure Java in the browser. Finish with a playable Tetris.

Course overview 12 steps

Othello in Java

12 steps. One level above Tetris. Finish with a minimax + α-β AI to play against.

Course overview 12 steps · 経験者向け

Java 復習クイズ

研修で習った Java の内容を未経験者目線で復習。間違えたら AI が解説。

Course overview 復習用 · 未経験者目線