Repetition and impasse

Sennichite: the same position four times

千日手 (sennichite) requires four occurrences with the same board, both hands, and side to move. JSA rules prescribe a replay with sente and gote exchanged; an online service may record a draw instead. A position with an extra pawn in hand is not the same position.

Perpetual check is the exception. A player who gives check on every one of their moves throughout the repeating sequence loses. Several checks in a row are legal; it is the continuous checking that produces fourfold repetition that breaks the rule.

Entering kings and impasse

Moving your king into the opposing camp is called 入玉 (nyūgyoku). It can make the king harder to attack, but does not itself end the game. When neither player has a realistic prospect of mating, an agreement or declaration procedure can settle the result. Do not assume that both kings entering the camp automatically makes a draw.

Count the right pieces

Piece	Points
Rook or bishop, promoted or not	5
Gold, silver, knight, lance, or pawn, promoted or not	1
King	0

The 38 non-king pieces total 54 points. These are impasse points, not estimates of how useful a piece is in an ordinary position. The rule determines which pieces enter your count.

• Agreement under the JSA 24-point rule: count your pieces across the whole board and in hand. Both players having at least 24 means a replay; a player below 24 loses. Some tournaments use a 27-point agreement rule, with the organizer specifying what happens at 27–27.
• JSA entering-king declaration: count only your pieces in the opposing camp and in hand. With the other conditions satisfied, 31 or more wins and 24–30 means a replay. A declaration failing the conditions loses.
• The online 27-point declaration rule: Shogi Wars, for example, requires 28 for sente and 27 for gote, counting the opposing camp and hand. “27-point” does not mean that either player wins with 27. Do not substitute the JSA 31-point threshold for a service’s own rule.

Declaration also requires your king in the opposing three ranks, at least ten of your other pieces there, no check on your king, and time remaining on your turn. Services differ in whether declaration is automatic or needs a button.

JSA rules also provide for a replay at 500 individual moves. If the 500th move gives check, the continuous checking sequence must end first. This is not a universal move cap for every app.

What to watch during a game

• 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 out, as long as you are not the one giving check, and as long as you know whether your event replays it or scores it a draw.
• 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. Check which rule your event or service uses before you rely on a number.
• 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 is judged the moment it happens and scored a draw, not replayed; if the repetitions came from checks by one side, that side loses. The engine can check an impasse declaration against the game’s point rule and refuses one that does not qualify, but the app does not yet give you a way to declare, so an entering-king game there is still decided on the board.

Rules and service examples

• Japan Shogi Association: articles 8–10
• Shogi Wars: entering-king conditions