S H O G I  R U L E S
====================

These are the rules of Shogi (Japanese chess), as distributed by the
Shogi-l listserver.  I have edited it slightly for clarity.

-- Mike


Shogi is a Japanese board game played by two players.  The object of the
game is to capture the opponent's King.  Shogi is played on a nine-by-nine
board.  The vertical rows are called files, the horizontal ones ranks or
just rows.  Each player has twenty pieces: one King, two Gold Generals, two
Silver Generals, two kNights, two Lances, one Rook, one Bishop and nine
Pawns.  The player moving up the board and making the first move is
referred to as black and his opponent white, although in Shogi sets all
pieces have the same colour.  They are differentiated only in direction:
pieces pointing away from a player are his.  The pieces lie flat on the
board and have their Japanese name written on them.


THE MOVES
---------

King:           one step in any direction per move
Gold General:   one step per move any way except diagnoally backward
                (as a king but not diagonally backward)
Silver General: one step per move forwards or diagonally
                (as a king but not sideways or vertically backward)
Knight:         one step to left or right, and two steps forward
                (the only piece which may jump over other pieces)
Rook:           moves vertically or horizontally any distance
Bishop:         moves diagonally any distance
Lance:          moves forward any distance
Pawn:           one step forward

Apart from the King and the Gold General all pieces can promote.
After promotion their moves are as follows:

+ Promoted Silver, promoted kNight, promoted Lance and promoted Pawn all
  move as a Gold.

+ The promoted Rook in addition to the moves of the unpromoted Rook can
  move one step in the diagonal directions. It either moves like a Rook
  or like a King.

+ The promoted Bishop in addition to the moves of the unpromoted Bishop
  can move one step horizontally or vertically. It either moves like a
  Bishop or like a King.


PROMOTION
---------

The three rows furthest away from a player are called the promotion zone. Apart
from the King and the Gold, any piece can be promoted to a more powerful piece
when it makes a move completely or partly in the promotion zone. So, when a
piece moves into, out of or fully inside the promotion zone it may be promoted
upon completion of its move. Promotion is optional, provided that the piece
still can make a legal move in case it is not promoted: if a Pawn or a Lance
move to the last row, or a Knight moves to either of the last two rows, it must
be promoted. In Shogi sets promoting a piece is done by turning this piece
upside down. Its promoted name is written on its other side.


CAPTURING AND DROPPING PIECES
-----------------------------

When one piece moves onto the same square as an opponent's piece, the
opponent's piece is captured. All pieces capture in the same way that they
move. Captured pieces become part of the capturer's force. In a later move,
instead of moving a piece on the board, a player may put a piece that he
has captured from his opponent back onto the board, in an empty square.
This is called dropping a piece. Pieces are always dropped unpromoted: if a
promoted piece is captured, it reverts to its unpromoted rank.  Pieces may
be dropped on any empty square on the board with only three restrictions:

 1) After dropping a piece it must be able to make a legal move. This applies
    to Pawns, Knights or Lances. They may not be dropped onto a square from
    which they will never be able to move.

 2) Attacking the King by dropping a Pawn on the square in front of him is not
    allowed if the King cannot prevent being captured on the following move.
    To use the Chess expression: checkmating the King with a Pawn drop is
    prohibited.

 3) A pawn may only be dropped on a file (vertical row) if there is no other
    unpromoted pawn of the same player on that file.


DRAWS
-----

The game of Shogi has very few draws (roughly 1 percent), mainly because of
the ability to drop pieces. Draws cannot be offered and can arise from two
situations:

 1) A position (including the pieces in hand) occurs 4 times with the same
    player to move ("Sennichite"). However, if this is caused by consecutive
    checks (direct attacks on the King, threatening to capture it on the next
    move) by one side, the player giving these checks loses the game.

 2) Both players have moved their King into the the promotion zone (or they
    cannot be prevented to do so) and the Kings cannot be checkmated. In
    that case the players may decide to count their pieces where the King
    does not count, the Rook and Bishop count as 5 points, and all other
    pieces as one point. Promotion is disregarded. If both players have at
    least 24 points the game is a draw ("Jishogi"). If a player has less,
    he loses the game.

    Of course, a player can refuse to count pieces when he still has mating
    chances or chances to gain material which would affect the outcome of the
    counting. There is no strict rule about what to do if this is not the case,
    but nonetheless a player refuses to count up (e.g. because he does not have
    enough points for a draw). It has been generally accepted that in such a
    case the game ends and the pieces are counted after one player has managed
    to get all his pieces protected in the promotion zone.

Chris Sterritt and Pieter Stouten, 12-th June 1990.
Last revision 9-th October 1991 - Draws (Jishogi rule).

