Tenjiku shogi

Tenjiku shogi (天竺将棋 tenjiku shōgi, "Indian chess" or 天竺大将棋 tenjiku dai shōgi "great Indian chess") is a large board variant of shogi (Japanese chess). The game dates back to the 15th or 16th century and was based on the earlier chu shogi, which itself was based on dai shogi. Because of the terse and often incomplete wording of the historical sources for the large shogi variants, except for chu shogi and to a lesser extent dai shogi (which were at some points of time the most prestigious forms of shogi being played), the historical rules of tenjiku shogi are not clear. Different sources often differ significantly in the moves attributed to the pieces. The descriptions listed here are a likely reconstruction based on chu shogi, the primary basis of tenjiku shogi, but not all contemporary players follow these historically based rules. It is not clear if the game was ever played much historically, as there is no record of sets ever having been made.

The objective of the game is to capture the opponent's king and, if present, the prince, which counts as a second king. Unlike standard shogi, captured pieces may not be dropped back into play by the capturing player.

Two players alternate making a move, with Black moving first. (The pieces are not differentiated by color; the traditional chess terms "Black" and "White" are only used to indicate who plays first, and to differentiate the sides during discussions of the game.) A move consists of moving a piece either to an empty square on the board or to a square occupied by an opposing piece, thus capturing that piece; and optionally of promoting the moving piece, if the move enters the promotion zone (that is, it starts outside the promotion zone and ends inside it), or if it is a capture and any part of it is in the promotion zone. Each of these options is detailed below. Despite the large size of the board and number of pieces, tenjiku shogi games are often quicker than smaller shogi variants because of the higher average power of the pieces. Good use of the fire demons can make for a short game.

Tenjiku shogi pieces that occur in chu shogi or dai shogi move as they do in that game, but the pieces from dai shogi promote differently. 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, that is, by another piece controlled by the moving player. The one exception to this is the unique burn of the fire demon. Each piece on 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 vice general, fire demon, lion hawk, lion, and knight are exceptions, in that they do not move, or are not required to move, in a straight line. Many pieces are capable of several kinds of movement, with the type of movement most often depending on the direction. The movement categories are:

Some pieces are limited to moving one square at a time. If a friendly piece occupies an adjacent square, the moving piece may not move in that direction; if an opposing piece is there, it may be displaced and captured. The step movers are the king, drunk elephant, blind tiger, ferocious leopard, gold general, silver general, copper general, iron general, dog, and pawn. Other pieces may step in certain directions, but move differently in other directions. Other pieces have a limited range of two squares along a straight line. The water buffalo, chariot soldier, vertical soldier, and side soldier may move one or two squares in certain directions. They can only move to the second square if the first is unoccupied. They may capture on either square, but must stop where they capture.

The lion, lion hawk, vice general, and fire demon may take multiple (2 to 3) steps in a single turn. These do not have to be in a line, so these pieces can potentially reach every square within two or three steps of the starting square, not just squares along one of the diagonals or orthogonals. Such moves are also useful to get around obstructions. An area mover must stop where it captures.

Some pieces can jump, or in the case of the knight can only jump: They pass over an intervening piece, whether friend or foe, with no effect on either. These are the free eagle, lion hawk, lion, soaring eagle, horned falcon, tetrarch, kirin, phoenix, and knight. These jumps all have a range of two squares: that is, the first square is passed over, and the piece lands (and captures) on the second. The knight jumps between the diagonals and orthogonals, and the lion and lion hawk may do so.

Many pieces can move any number of empty squares along a straight orthogonal or diagonal line, limited only by the edge of the board. If an opposing piece intervenes, it may be captured by moving to that square and removing it from the board. A ranging piece must stop where it captures, and cannot bypass a piece that is in its way. If a friendly piece intervenes, the moving piece is limited to a distance that stops short of the intervening piece; if the friendly piece is adjacent, it cannot move in that direction at all. The ranging pieces are the great general, vice general, rook general, bishop general, free eagle, soaring eagle, horned falcon, queen, water buffalo, chariot soldier, fire demon, lion hawk, dragon king, dragon horse, rook, bishop, vertical mover, side mover, reverse chariot, vertical soldier, side soldier and lance.

The lion, lion hawk, free eagle, soaring eagle and horned falcon have sequential multiple capture abilities, called "lion moves". The fire demon can "burn" multiple pieces simultaneously. These unusual moves are described below.

The heavenly tetrarch cannot move to an adjacent square, and has other idiosyncrasies; the fire demon 'burns' adjacent pieces. This is best described below.

A player is not allowed to make a move that would return the board to a previous position, with the same player to move. This rule prevents games from entering into a repeated loop. However, evidence from chu shogi problems suggests that this at least does not apply to a player who is in check or whose pieces are attacked, as otherwise one could win via perpetual check or perpetual pursuit. The modern chu shogi rule as applied by the Japanese Chu Shogi Association (JCSA) is as follows, and presumably tenjiku shogi should be similar. If one side is making attacks on other pieces (however futile) with his moves in the repeat cycle, and the other is not, the attacking side must deviate, while in case of checking the checker must deviate regardless of whether the checked side attacks other pieces. In the case of consecutive passes, the side passing first must deviate, making turn passing to avoid zugzwang pointless if the opponent is in a position where he can pass his turn too. If none of these are applicable, repetition is a draw.

In the diagrams below, the different types of moves are coded by symbol and by color: blue for step moves, green for multiple capture, red for range moves, yellow for jumps, and orange for ranging jumps. Notation ☆ Jumps to this square, bypassing any intervening piece. ○ Steps a limited number of squares along a straight line. ● Steps within an area, not restricted to a straight line. Must stop upon capture. ☆ Jumps to this square, then continues as a step mover. ● Steps a limited number of squares within an area, and may capture more than once. ! igui (capture without moving). Counts for two steps. ☆ May jump directly to this square, or reach it through a multiple move. │ Ranges along a straight line, crossing any number of empty squares ─ ╲ ╱ ☆ Jumps to this square, then continues as a range mover. │ Jumps along a straight line, crossing any number of squares, but only when making a capture; otherwise, moves exactly as a ranging piece. ─ ╲ ╱ ※ Burns any adjacent enemy pieces wherever it stops (background color indicates movement).

A player may not make a move if the resulting position is one that has previously occurred in the game with the same player to move. This is called repetition (千日手 sennichite). Note that certain pieces have the ability to pass in certain situations (lions, soaring eagles, horned falcons, vice generals, fire demons, free eagles, and lion hawks). Such a pass move leaves the position unchanged, but it does not violate the repetition rule, as it will now be the turn of the other player to move. Of course, two consecutive passes are not possible, as the first player will see the same position as before. However, evidence from chu shogi problems suggests that this at least does not apply to a player who is in check or whose pieces are attacked, as otherwise one could win via perpetual check or perpetual pursuit. The modern chu shogi rule as applied by the Japanese Chu Shogi Association (JCSA) is as follows, and presumably tenjiku shogi should be similar. If one side is making attacks on other pieces (however futile) with his moves in the repeat cycle, and the other is not, the attacking side must deviate, while in case of checking the checker must deviate regardless of whether the checked side attacks other pieces. In the case of consecutive passes, the side passing first must deviate, making turn passing to avoid zugzwang pointless if the opponent is in a position where he can pass his turn too. Only the fourth repetition is forbidden by these rules. If none of these are applicable, repetition is a draw.

When a player makes a move, such that the opponent's only remaining king or prince could be captured on the following move, the move is said to give check; the king or prince is said to be in check. If a player's last king or prince is in check and no legal move by that player will get it out of check, the checking move is also mate, and effectively wins the game. Unlike Western chess, a player need not move out of check in tenjiku shogi, and indeed may even move into check. Although obviously not often a good idea, a player with more than one royal may occasionally sacrifice one of these pieces as part of a gambit.

A player who captures the opponent's sole remaining king or prince wins the game. Thus a player who is checkmated or stalemated will lose. The very artificial situation of a smothered stalemate, where no moves are possible (even those that would expose the king), is not covered in the historical sources. On their pages for chu shogi and dai shogi, The Chess Variant Pages rule this as a loss for the stalemated player, for definiteness. In practice these winning conditions are rarely fulfilled, as a player will typically 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.)

Games between players of disparate strength may be played with handicaps, by analogy with chu shogi. 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. (As the first move can cancel out weak handicaps, either the weaker player or the stronger can be White, as needed.) However, no historical handicap system is known, unlike for chu shogi.

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 modifications have been made for tenjiku shogi. A typical example is P 8g. The first letter represents the piece moved (see above). Promoted pieces have a + added in front of the letter. e. g., +P for a promoted pawn. The designation of the piece is followed by a symbol indicating the type of move: for an ordinary move or x for a capture. 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 16p being the bottom left corner. (This method of designating squares is based on Japanese convention, which, however, uses Japanese numerals instead of letters. For example, the square 2c is denoted by 2三 in Japanese.) If a lion, horned falcon, soaring eagle or Heavenly Tetrarch captures by igui, or the fire demon burns, the square of the piece being captured is used instead of the destination square, and this is preceded by the symbol !. A piece moving next to a fire demon (suicide move) is followed by a *. If a double or triple capture is made, than subsequent captures are added after the first capture. 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, Nx7d= indicates a knight capturing on 7d 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.