Shogi Japanese Chess
Play a full 9×9 game against the browser or pass one device between two players. Drops, promotion, nifu, pawn-drop mate protection, legal-move guidance, autosave, hints and local review are built in — no account required.
Build a practice position
Place pieces, set pieces in hand and choose whose turn it is. Starting from a custom setup is marked Assisted.
Promote this piece?
Promotion is optional on this move.
Game recordMove list & notation0 plies
Game record
Advanced training & analysisMove evidence, fixed-rule drills, SFEN and local backup
Exact Rule & Move Evidence Lab
Every player move is re-read from the same local legal engine: drops, promotion, capture, check, legal replies and a disclosed lightweight material/mobility heuristic delta. The heuristic is a local comparison aid, not a claim that a move is objectively best.
Play a move to build exact local rule evidence.
Completed-game review
Finish a local game and your own decision evidence will stay on this device.
Fixed Rules Benchmark · same 20 questions
Five rule families × four questions: drops/nifu, promotion, movement, king safety and repetition/record. Clean 5 compares only five uninterrupted runs of the identical fixed set.
Choose Fixed Benchmark or Adaptive Drill.
Ready for a fixed or adaptive rule run.
SFEN & reproducible local record
Copy the current board as standard SFEN, load a local SFEN, copy a setup link, or copy this game’s local move record. Imported/shared positions are marked Assisted so normal clean-game records stay honest.
Local evidence backup & accessibility
Export/import only this browser’s Shogi stats and V0.205 evidence. Display preferences do not alter rules or benchmark identity.
Captured pieces become your reserve
Except for the king, a captured piece changes sides, loses promotion, and enters your hand. On a later turn you can drop one reserve piece onto a legal empty square instead of moving a board piece.
Upgrade pieces in the far three ranks
Rook, bishop, silver, knight, lance and pawn may promote when entering, leaving or moving inside the opponent’s three-rank zone. Pawn and lance must promote on the last rank; knight must promote on the last two.
Nifu and drop-mate rules matter
You cannot drop an unpromoted pawn on a file that already contains one of your unpromoted pawns. This implementation also rejects an immediate checkmate delivered by a pawn drop.
Check must be answered
Every move and drop is filtered for king safety. A player with no legal reply while in check loses by checkmate; a position with no legal move also ends the game.
Local fourfold loop protection
Four identical positions trigger repetition. V0.316 also detects a continuous-check repetition in the recorded loop and awards the game against the side that kept checking; ordinary repetition is a draw.
No account or invented rating
Hints, Undo and Restart mark the game Assisted. Stats and Daily history stay in this browser. There is no fake dan/kyu rank, no wagering, chips, prizes or paid-random mechanic.