peer2peergames

Shogi

Japanese chess, on a board of nine by nine squares. The rule that makes it different from every other chess: a piece you capture changes sides. It goes into your hand, and on a later turn you may drop it back onto the board as your own.

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The board and the pieces

  1. Nine files by nine ranks of squares, and the pieces stand in the squares.
  2. Each side has twenty pieces: a king, a rook, a bishop, two golds, two silvers, two knights, two lances and nine pawns.
  3. Both sides' pieces are the same colour. They are wedge shaped, and each points at the opponent: that is how you tell whose a piece is. On this site the opponent's pieces are also lightly tinted.
  4. Black moves first. On this site the seed decides which seat plays Black.

How the pieces move

  1. The king moves one square in any direction.
  2. The rook moves any distance straight along a rank or a file, and the bishop any distance diagonally. Neither jumps.
  3. A gold moves one square straight in any direction, or one square diagonally forward. It cannot go diagonally back.
  4. A silver moves one square diagonally in any direction, or one square straight forward. It cannot go straight sideways or straight back.
  5. A knight jumps to one of the two squares two ahead and one to the side, jumping over anything between. It only ever goes forward.
  6. A lance moves any distance straight forward and never backward or sideways.
  7. A pawn moves one square straight forward, and it takes the same way, by moving onto the piece in front of it. Unlike chess, it does not take diagonally.

Capturing, and the hand

  1. You capture a piece by moving onto its square. There is no capture by jumping.
  2. A captured piece is not out of the game. It goes into your hand and is yours from then on.
  3. The pieces in each player's hand are shown beside the board, with how many of each.

The drop

  1. Instead of moving a piece, you may take one from your hand and put it on any empty square. That is your whole turn.
  2. A piece is always dropped unpromoted, even into the far three ranks.
  3. You may not drop a piece where it could never move again: a pawn or a lance on the last rank, or a knight on either of the last two.
  4. You may not drop a pawn on a file where you already have an unpromoted pawn (two pawns, nifu).
  5. You may not drop a pawn to give checkmate (uchifuzume). A pawn drop that checks is allowed, and so is a pawn MOVED to give mate.

Promotion

  1. The far three ranks are the promotion zone, marked by the four dots on the board.
  2. When a piece moves into the zone, out of it, or within it, it may promote: it turns over. Promoting is your choice, and the board asks.
  3. A promoted rook (the dragon) also moves one square diagonally, and a promoted bishop (the horse) also one square straight.
  4. A promoted silver, knight, lance or pawn moves like a gold. The king and the golds never promote.
  5. A piece that would otherwise never move again must promote: a pawn or a lance reaching the last rank, a knight reaching either of the last two.
  6. A promoted piece that is captured goes into the hand as its unpromoted self.

How a game ends: check and mate

  1. Check is an attack on the king. You may not leave your king in check, and the board will not let you.
  2. Checkmate wins: the king is attacked and nothing can answer it.
  3. A player with no legal move at all loses. With drops this almost never happens, but this site reads the rules that way.
  4. A player may resign, and either may offer a draw for the other to accept.
  5. A missed move deadline is a loss, exactly like resigning.

Repetition

  1. When the same position, with the same pieces in hand and the same side to move, comes round for the fourth time, the game is a draw (sennichite).
  2. Except perpetual check: if every one of one side's moves in the repetition gave check, that side loses.

The impasse

  1. When both kings have walked into the enemy camp, neither may ever be mated. The game is then decided by declaring.
  2. This site uses the 27-point declaration, the one computer shogi uses: on your turn you may declare if your king is in the enemy camp, ten of your other pieces are in the enemy camp, your king is not in check, and you have 28 points if you are Black or 27 if you are White.
  3. Points are counted only from your pieces in the enemy camp and in your hand: a rook or a bishop, promoted or not, counts five, and every other piece but the king counts one.
  4. A correct declaration wins, and the board only offers it when it is correct. The version of this rule played with clocks also asks for time remaining; there is no clock here, so that condition is dropped.

The rules this site chose

  1. You cannot make an illegal move here, so an illegal move never loses a game as it would in a tournament.
  2. A repetition is a draw and the game ends there; there is no replay.
  3. A game that has not ended after 500 moves is drawn, as the Japan Shogi Association's rule has it. A player in check at that point plays on until they are not.
  4. Who plays Black is decided by the seed, not by the pawn toss (furigoma).

Kanji or icons

  1. The pieces show their kanji by default, as real pieces do; a promoted piece shows its promoted name in red.
  2. The button under the board switches every piece to icons, and back. Your choice is remembered on this device only.
  3. An icon shows how the piece moves: a dot is one step that way, an arrow is any distance that way, and the knight shows its two jumps. A promoted piece is red and has a ring at its centre.

Shogi is the chess of Japan. If you know chess, the moves will feel familiar; the drop will not, and it changes everything: a piece you take is a piece you can use.

Shogi terms

The hand
The pieces you have captured. They are yours, and you may drop one onto the board instead of moving.
A drop
Putting a piece from your hand onto an empty square. It arrives unpromoted.
The zone
The far three ranks. A piece moving into, out of or within it may promote.
Nifu
Two unpromoted pawns of yours on one file. Dropping a pawn to make it is not allowed.
Uchifuzume
Dropping a pawn to give checkmate. Not allowed.
Sennichite
The same position four times: a draw, unless one side gave check every move.
The impasse
Both kings safe in the enemy camp. Decided here by the 27-point declaration.
Hodges and Japanese notation
The two ways this site writes a move: P-7f in Western notation, or the Japanese form for a reader whose language is Japanese.

Playing it here

  • Against a person or the bot. The bot needs no account and starts at once. To play a person, be rated and keep your games, you need an account: an email address and a password.
  • At your own pace. Every move has a deadline you both see, from one minute to a week. A game can take an evening or it can take a fortnight.
  • Nothing to buy and nothing to win. No stakes, no prizes, no boosts, no undo. The only thing on offer is a place on a leaderboard, and only if you want one.
  • Every game can be checked. Anything decided by chance comes from the game's seed, and the seed is published the moment the game ends, so any finished game can be replayed and verified by anyone. See fair play.