Learn · 千日手と持将棋
Repetition and impasse.
Most shogi games end in checkmate, and shogi produces far fewer draws than chess because captured pieces come back. But two endings are not mate, and one of them turns what looks like a draw into a loss for the player who caused it.
Sennichite: the same position, four times
千日手 (sennichite, "a thousand-day game") is shogi's repetition rule. When the same position occurs four times with the same side to move and the same pieces in hand, the game is a draw. In a tournament the players then replay it with colours swapped, which is why the word means what it means: without the rule, the game could go on for a thousand days.
Note the difference from chess. It is four occurrences, not three, and there is no claim to make: it simply is a draw when it happens. Both players' hands must match too, so a repetition where one side has quietly gained a pawn is not a repetition at all.
If those repetitions were produced by one player giving check every time, it is not a draw. The player who kept checking loses. This is the opposite of chess, where perpetual check is the classic way to save a lost position, and it is the single rule most likely to catch out a chess player. In shogi, a losing player cannot check their way out.
The rule is symmetrical in a way worth noticing: it does not matter who is winning, only who is doing the checking. A player far ahead on material who runs a perpetual check to close the game out loses it.
Impasse: two kings that cannot be caught
持将棋 (jishogi) is the other ending. A king that reaches the far side of the board is very hard to mate, because most pieces only attack forwards. When both kings walk into their opponent's promotion zone and neither side can force mate, the game is stuck: no amount of play will produce a checkmate.
How the counting works
Instead of playing on, a player declares. The material each side holds — on the board in the promotion zone, and in hand — is scored:
| Piece | Points |
|---|---|
| Rook or bishop, promoted or not | 5 |
| Every other piece except the king | 1 |
| The king itself | 0 |
All twenty non-king pieces are worth 54 points in total, so an even split is 27 each. Two rules are in use, and the app supports both:
- The 27-point rule, used in professional play and by most servers. The declaring player needs at least 27 points and wins outright; below that they lose. There is no draw, which is why it is preferred for a rated game.
- The 24-point rule, the older amateur convention. 24 or more draws, and the game is replayed.
A declaration also has conditions beyond the points: the king must be in the promotion zone, the declaring side must have at least ten other pieces there, and the king must not be in check. A declaration that fails its conditions loses the game immediately, so it is not a move to guess at.
What this means when you play
- Do not chase a lost game with checks. The rule that saves you in chess loses you the game here. If your only continuation is perpetual check, you were already lost, and now you have made it official.
- A repetition is a real result. If you are worse, steering into a fourfold repetition is a legitimate way to save half a point, as long as you are not the one giving check.
- Entering the king is a plan, not an accident. Against an opponent with no pieces aimed at your side of the board, walking the king forward is a known winning technique, and the point count is what you are playing for once you start.
- Both endings are rare. Roughly one or two professional games in a hundred end this way. Drops keep material on the board, and a game with material still on it usually finds a mate.
In the app
Both rules are enforced by the same engine that validates every move. A fourfold repetition ends the game as a draw, unless the repetitions came from checks by one side, in which case that side loses. Impasse is a declaration you make, checked against the point rule the game was configured with, and a declaration that does not qualify is refused rather than played.
Both rules, enforced at the table.
The app judges repetition and impasse with the same engine that checks every move, so a game never ends in an argument.