Cannon shogi

Cannon shogi (大砲将棋, "taihō shōgi", cannon chess) is a modern variant of shogi (Japanese chess). It was invented by Peter Michaelsen in February 1998.
Rules of the game.
Objective.
The objective of the game is to capture your opponent's king.
Game equipment.
Two players, Black and White (or 先手 "sente" and 後手 "gote"), play on a board ruled into a grid of 9 "ranks" (rows) by 9 "files" (columns). The squares are undifferentiated by marking or color.
Each player has a set of 20 wedge-shaped pieces, of slightly different sizes. From largest to smallest (most to least powerful) they are:
Most of the English names correspond to rough equivalents in Western chess, rather than as translations of the Japanese names.
Each piece has its name in the form of two kanji written on its face. On the reverse side of some pieces are two or three other characters, often in a different color (commonly red instead of black); this reverse side is turned up to indicate that the piece has been promoted during play. The pieces of the two sides do not differ in color, but instead each piece is shaped like a wedge, and faces forward, toward the opposing side. This shows who controls the piece during play. The game is often played with "Westernized" (or "international") pieces, which replace the kanji with more intuitive symbols, such as pictorial icons.
Table of pieces.
Listed here are the pieces of the game and, if they promote, which pieces they promote to.
English speakers sometimes refer to promoted bishops in shogi and its variants as "horses" and promoted rooks as "dragons", after their Japanese names, and generally use the Japanese name "tokin" for promoted pawns. Silver generals and gold generals are commonly referred to simply as "silvers" and "golds".
The characters on the backs of the pieces that promote to gold generals are cursive versions of 金 'gold', becoming more cursive (more abbreviated) as the value of the original piece decreases. These abbreviated characters have these equivalents in print: 全 for promoted silver, 今 for promoted knight, 仝 for promoted lance, and 个 for promoted pawn ("tokin"). Another convention has abbreviated versions of the "original characters", with a reduced number of strokes: 圭 for promoted knight, 杏 for promoted lance, with promoted silver the same 全 as above, and と for "tokin".
Setup.
Each side places his pieces in the positions shown below, pointing towards the opponent.
That is, the first rank is |L|N|S|G|K|G|S|N|L|.
Game play.
The players alternate making a move, with Black moving first. (The traditional terms 'Black' and 'White' are used to differentiate the sides during discussion of the game, but are not literally descriptive.) A move consists of moving a single piece on the board and potentially "promoting" that piece, displacing ("capturing") an opposing piece or "dropping" a captured piece onto an empty square of the board. Each of these options is detailed below.
Movement and capture.
An opposing piece is captured by "displacement": That is, if a piece moves to a square occupied by an opposing piece, the opposing piece is displaced and removed from the board. A piece cannot move to a square occupied by a friendly piece (meaning another piece controlled by the moving player).
Each piece in the game moves in a characteristic pattern. Pieces move either "orthogonally" (that is, forward, backward, left, or right, in the direction of one of the arms of a plus sign, +), or "diagonally" (in the direction of one of the arms of a multiplication sign, ×). The knight is an exception in that it does not move in a straight line.
Pawn.
The pawn moves and captures a single square forwards or sideways, like the "soldier" of Korean chess (janggi). It promotes (optionally) to a "tokin" (gold general) when making a move that begins or ends in the last 3 ranks of the board.
Lance.
The lance has the same move as in shogi. It may move any number of empty squares forwards (i.e.: in the same file), capturing the first opposing piece it encounters. The lance promotes (optionally) to a gold general when ending a move in the second or third last ranks of the board. If ending its move in the final rank it must promote.
Knight.
The knight has the same move as its equivalent in shogi. It may move one square forward followed by one square diagonally forward to a square that is either empty or occupied by an opposing piece, jumping over any intervening piece of either side in the first square. If landing on a square occupied by an opposing piece that piece is captured. The knight promotes (optionally) to a gold general when ending a move in the third last rank of the board. If ending its move on either of the final two ranks it must promote.
Silver General.
The silver general is the same as in shogi. It moves and captures a single square forwards or diagonally in any direction. It promotes (optionally) to a gold general when making a move that begins or ends in the last 3 ranks of the board.
Gold General.
The gold general is the same as in shogi. It moves and captures a single square diagonally forwards or orthogonally in any direction. It does not promote.
Bishop.
The bishop is identical to that in shogi. It may move any number of empty squares in any diagonal direction, capturing the first opposing piece it encounters. The bishop may optionally promote to a dragon horse when beginning or ending a move in one of the final 3 ranks on the board. As a dragon horse it may either move as a bishop or move one square orthogonally.
Rook.
The rook is the same as in shogi. It may move any number of empty squares in any orthogonal direction, capturing the first opposing piece it encounters. The rook may optionally promote to a dragon king when beginning or ending a move in one of the final 3 ranks on the board. As a dragon king it may move either as a rook or one square diagonally.
Gold Cannon.
The gold cannon moves as a rook, by sliding any number of empty squares along a row or column, but can capture an enemy only if there is another piece (of either side) in between. Thus to capture the gold cannon leaps over the intervening piece and lands on the enemy piece, like a cannonball. This is the same move and capture as the "cannon" (Pao) of Chinese chess (xiangqi). The gold cannon may promote (optionally) if it begins or ends its move in one of the last 3 ranks of the board. On promotion it becomes a flying gold cannon. As a flying gold cannon it may move orthogonally over whole rows and is able to leap one piece while moving. Additionally, it can move one square diagonally, or move or capture two squares diagonally, by leaping an adjacent piece.
Silver Cannon.
The silver cannon captures in the same way as the gold cannon, but can only move by leaping over an intervening piece, called a "screen". This is the move and capture of the "cannon" (Po) of Korean chess (janggi). The silver cannon may promote (optionally) if it begins or ends its move in one of the last 3 ranks of the board. On promotion it becomes a flying silver cannon. As a flying silver cannon it has the same powers as the flying gold cannon. It may therefore move orthogonally over whole rows and is able to leap one piece while moving. It can also move one square diagonally, or move or capture two squares diagonally, by leaping an adjacent piece.
Copper Cannon.
The copper cannon moves as a bishop, by sliding any number of empty squares in a diagonal direction, but can capture an enemy only if there is another piece (of either side) in between. Thus to capture the copper cannon leaps over the intervening piece and lands on the enemy piece, like a cannonball. This is the same move and capture as the gold cannon, but in a diagonal rather than orthogonal direction. The copper cannon may promote (optionally) to a flying copper cannon if it begins or ends its move in one of the last 3 ranks of the board. As a flying copper cannon it gains the power to move diagonally over whole rows to leap one piece while moving. Additionally, it can move one square orthogonally, or move or capture two squares orthogonally, by leaping an adjacent piece.
Iron Cannon.
The iron cannon captures in the same way as the copper cannon, but can only move by leaping over an intervening piece, called a "screen". The iron cannon may promote (optionally) to a flying iron cannon if it begins or ends its move in one of the last 3 ranks of the board. As a flying iron cannon it has the same powers as the flying copper cannon. It may therefore move diagonally over whole rows and is able to leap one piece while moving. It can also move one square orthogonally, or move or capture two squares orthogonally, by leaping an adjacent piece.
King.
The king has the same move as in shogi. It may move one square in any direction.
Promotion.
A player's "promotion zone" consists of the three farthest ranks, at the original line of the opponent's pawns and beyond (that is, the opponent's territory at setup). If a piece "crosses" the board within the promotion zone, including moving into, out of, or wholly within the zone, but "not" including drops (see below), then that player may choose to "promote" the piece at the end of the turn. Promotion is effected by turning the piece over after it moves, revealing the name of its promoted rank.
Promoting a piece has the effect of changing how that piece moves until it is captured and removed from the board.
If a piece that cannot retreat or move aside advances across the board until it can no longer move, it must be promoted. This applies to the lance, upon reaching the farthest rank, and to the knight upon reaching either of the two farthest ranks.
When captured, pieces lose their promoted status.
Movement diagrams.
Below are diagrams indicating each piece's movement. Pieces are paired with their promotion. Pieces with a gray heading start out in the game; those with a blue heading only appear on the board after promotion. Betza's funny notation has been included in brackets for easier reference.
Drops.
Captured pieces are truly "captured" in cannon shogi. They are retained "in hand", and can be brought back into play under the capturing player's control. On any turn, instead of moving a piece on the board, a player can take a piece he has previously captured and place it on any empty square, facing the opponent. The piece is now part of the forces controlled by that player. This is termed "dropping" the piece, or just a "drop".
A drop cannot capture a piece; that requires an additional move.
Pieces that are dropped in the promotion zone do not promote as a result: Promotion requires that piece make a normal movement on a subsequent turn, as detailed under "Promotion", above.
No knight or lance may be dropped on the farthest rank, since it would have no legal move on subsequent turns. Similarly, a knight may not be dropped on the penultimate rank.
Unlike in shogi, there are "no" additional restrictions when dropping pawns: a pawn "can" be dropped into the same file (vertical column) as another unpromoted pawn controlled by the same player. Also a pawn "can" be dropped to check the opponent's king, if the opponent would have no way to prevent his king being captured on the next move. In other words, a pawn "can" be dropped to give immediate mate.
Check and mate.
When a player makes a move such that the opponent's king could be captured on the following move, the move is said to "give check" to the king; the king is said to be "in check". If a player's king is in check and no legal move by that player will get the king out of check, the checking move is also "mate", and effectively wins the game.
A player is not allowed to give perpetual check.
Game end.
A player who captures the opponent's king wins the game. In practice this rarely happens, as a player will resign when checkmated, as otherwise when loss is inevitable.
A player who makes an illegal move loses immediately. (This rule may be relaxed in casual games.)
There are two other possible (but fairly uncommon) ways for a game to end: repetition (千日手 "sennichite") and impasse (持将棋 "jishōgi").
If the same position occurs four times with the same player to play, then the game is no contest. (Recall, however, the prohibition against perpetual check.) For two positions to be considered the same, the pieces in hand must be the same, as well as the position on the board.
The game reaches an impasse if both kings have advanced into their respective promotion zones and neither player can hope to mate the other or to gain any further material. If this happens then the winner is decided as follows: each rook, bishop and cannon scores 5 points for the owning player, and all other pieces (except kings) score 1 point each. Promotions are ignored for the purposes of scoring. A player scoring less than 38 points loses. If both players have at least 38 points, then the game is no contest.
Games which are no contest are usually counted as draws in amateur tournaments, but in professional style tournaments the rules typically require the game to be replayed with colors reversed (possibly with reduced time limits).
Handicaps.
Games between players of disparate strength are often played with handicaps. In a handicap game, one or more of White's pieces is removed before the start of play, and White plays the first move of the game. Note that the pieces removed at the beginning play no further part in the game - they are not available for drops. The imbalance created by this method of handicapping is not as strong as it is in chess, because material advantage is not as powerful in shogi as in chess.
Game notation.
The method used in English-language texts to express shogi moves was established by George Hodges in 1976. It is derived from the algebraic notation used for chess, but differs in several respects.
A typical example is P-8f.
The first letter represents the piece moved: P = pawn, L = lance, N = knight, S = silver, G = gold, GC = gold cannon, SC = silver cannon, IC = iron cannon, CC = copper cannon, B = bishop, R = rook, K = king.
Promoted pieces have a + added in front of the letter. e.g., +P for a tokin (promoted pawn).
The designation of the piece is followed by a symbol indicating the type of move: - for an ordinary move, x for a capture, or * for a drop.
Next is the designation for the square on which the piece lands.
This consists of a number representing the file and a lowercase letter representing the rank, with 1a being the top right corner (as seen from Black's point of view) and 9i being the bottom left corner.
If a move entitles the player to promote the piece, then a + is added to the end to signify that the promotion was taken, or an = to indicate that it was declined.
For example, Nx7c= indicates a knight capturing on 7c without promoting.
In cases where the above notation would be ambiguous, the designation of the start square is added after the designation for the piece in order to make clear which piece is meant.
Moves are commonly numbered as in chess.
In handicap games White plays first, so Black's move 1 is replaced by an ellipsis.
Nature of the game.
With the introduction of the cannons of Chinese and Korean chess, as well as their diagonal counterparts, the inventor wanted to add a new dimension to the classical game of shogi. With a pawn array similar to the one used in Chinese and Korean chess, the opening game tends to be much more tactical and explosive than in ordinary shogi. Not only because of their high number, the cannons dominate play more than in xiangqi and janggi. Because of the drops, they are more mobile and dangerous in all phases of the game. They may be weakened a little on board, as more and more pieces are captured and kept in hand, but may still be very useful when dropped on the board again, or when other pieces are dropped in front of them.
The Pawns move and capture sideways as well as forwards, because the inventor thought that they needed some compensation, being only 2x5 against 2x15 officers.