Sudoku Chess — Play Online for Free
Sudoku Chess is a thrilling chess variant where every move must respect Sudoku numbering rules — each piece has a number, and no number can repeat in the same row, column, or 3×3 box. Free to play online at sudoku-chess.com.
What is Sudoku Chess?
Sudoku Chess, invented by Greg Hoffmann, is a novel chess variant that merges chess with Sudoku on a 9×9 board subdivided into nine 3×3 boxes. Like classic chess, both the piece set and the initial board setup are fixed. Each piece is assigned a Sudoku number from 1–9, and no piece may move to the same rank, file, or 3×3 box as another piece of the same number.
The check and checkmate rules are also modified: a king is only in check if the attacking piece can legally complete the capture under Sudoku rules — a same-numbered defender near the king acts as a shield. This creates entirely new strategic and tactical patterns not found in classic chess.
Features
- Play live online matches against other players worldwide
- Daily games with streak tracking
- Curated Sudoku Chess puzzles to sharpen your skills
- Challenge friends with a private invite link
- Play against computer bots at multiple difficulty levels
- Free to play — no download required in a browser
Learn the Rules
Read the full game guide — official rules, special move variations for castling, promotion, and en passant, and the origin story — on the About & Rules page.
Rules & About →
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Created by Greg Hoffmann · greg@sudoku-chess.com