Tenjiku shogi

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, Black and White (or 先手 sente and 後手 gote), play on a board composed of squares in a grid of 16 ranks (rows) by 16 files (columns) with a total of 256 squares. The squares are undifferentiated by marking or color. A pair of dots may be placed just beyond the fifth rank on each side to mark the promotion zones and aid in the initial setup of the two camps.

Each player has a set of 78 wedge-shaped pieces of 36 types. In all, the players must remember 43 moves for these pieces. The pieces are of slightly different sizes. From largest to smallest (roughly most to least powerful) they are:

Several of the English names were chosen to correspond to rough equivalents in Western chess, rather than as translations of the Japanese names.

Each piece has its name in the form of one or two kanji written on its face. On the reverse side of some pieces are two or three other characters, often in a different color such as red; 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.

Listed below are the pieces of the game and, if they promote, which pieces they promote to. Pieces marked with an *asterisk are only available with promotion.

The promotions can be summarized as series of promotion chains, as follows. Within each block below, a piece (except the kings) promotes to the piece above it. Pieces at the top of each block do not promote (and if in italics, and with an *asterisk, as stated before, these appear only upon promotion). Note that pieces may only promote once. For example, a gold general promotes to a rook, and a rook promotes to a dragon king, but a gold general promoted to a rook cannot promote a second time to a dragon king. This is clear from the equipment, for each piece only has two sides.

The initial setup of the board is as follows. See below for a description of the types of moves involved.

Full names

Abbreviated names

Transcribed abbreviations

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.

A few powerful pieces may jump over any number of pieces (including zero), friend or foe, along a diagonal or orthogonal, but only when making a capture. These are the great general, vice general, rook general, and bishop general.

However, they may only jump over other pieces of lower rank, whether friend or foe. None may jump a king or prince of either side. The relevant ranking is:

1. King, prince
2. Great general
3. Vice general
4. Rook general, bishop general

That is, bishop and rook generals cannot jump over any other range-jumping piece.

The range jumpers can nevertheless capture each other, even if they cannot jump over each other and there are other pieces outside the ranking in the way. (For example, though a rook general cannot jump over an enemy great general, it may still capture the great general.) They cannot capture a king or prince by jumping, but can do so without jumping.

Some descriptions of the game do not limit this ability to moves making a capture. However, most mention that these pieces have two types of move, ranging and range jumping, suggesting that the capture rule may have been mistakenly omitted.

The lion, lion hawk, 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.

Tenjiku shogi pieces that occur in chu shogi promote as they do in that game, with the exceptions of the lion and queen, which do not promote in chu shogi.

A player's promotion zone consists of the five far ranks, at the original line of the opponent's pawns and beyond. When a promotable piece makes a move entering the promotion zone, or makes a capture within the promotion zone—including captures entering, leaving, or entirely within the zone—it has the option of "promoting" to a more powerful rank.

Pieces which take multiple steps per move are probably not allowed to promote by crossing into the promotion zone and back out again: this is not explicitly stated in the rules, and chu shogi does not offer guidance here because such pieces do not promote in chu shogi, but it would contravene the usual stipulation that the move start outside and end inside the promotion zone. Another small piece of evidence is that the fire demon's burn is only calculated at the end of a turn, like promotion, and it does not apply to intermediate steps in the move. For similar reasons, igui or capturing probably does not allow promotion if the move begins and ends outside the promotion zone, even if it passes in and back out along the way.

Promotion is effected by turning the piece over after it moves, revealing the name of its promoted rank. As such, a promoted piece cannot then promote a second time. Promotion is never mandatory, and in some cases it may be beneficial to leave the piece unpromoted. Promotion is permanent and promoted pieces may not revert to their original rank.

Promoting a piece has the effect of changing how that piece moves. See above for what each piece promotes to and below for how they move.

The king, great general, vice general, free eagle, lion hawk, and fire demon do not promote, nor can already promoted pieces promote further.

If a piece is not promoted upon entering the promotion zone, then it may not promote until it leaves the zone and reenters unless it makes a capture.

If a piece which cannot retreat or move to the side advances to the far rank, so that it would otherwise have no further legal move, it is trapped. These pieces are the pawn, knight, iron general, and lance. In practice this would never occur for pawns or lances, which promote to pieces which keep their old moves, so that there is never any reason to defer their promotion, as stalemate is a loss for the stalemated player.

The situation for the knight and iron general, which promote to pieces that do not keep their old moves, is unclear. Since there could be a reason to defer their promotion, it is possible that they receive a second chance to promote at the far rank on a non-capture, as in chu shogi. (In chu shogi, this provision applies to pawns, which are not completely upward compatible with the gold generals they promote to because of the rules against trading lions.) This second chance, if it exists, can likewise be declined, leaving the knight or iron general as an immobile "dead piece" (死に駒). However, this is uncertain, because it is not clear when the rule of pawn promotion was added to chu shogi (before or after the invention of tenjiku shogi), and because the Edo-era sources have numerous lacunae in the rules for the variants other than sho shogi and chu shogi.

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.

Pieces are arranged in this section so that, if they promote, they promote into the piece above them. Piece names with a grey background are present at the start of the game; those with a blue background only appear with promotion. Betza's funny notation has been included in brackets for easier reference, with the extension that the notation xxxayyyK stands for an xxxK move possibly followed by an yyyK move, not necessarily in the same direction. Larger numbers of 'legs' can be indicated by repeated application of 'a', or by numbers: thus a3K means a piece that can take up to three steps of a king. By default continuation legs can go into all directions, but can be restricted to a single line by a modifier 'v' ("vertical", interpreted relative to the piece's current position on its path). The default modality of all legs is the ability to move and capture: other possibilities are specified explicitly. Thus mKa3K means a piece that takes up to three steps of a king, but must stop when it first captures. Square brackets are used to make it clear what legs the a modifier chains together: thus DaK would denote a dabbaba move followed by a king move, but D[aK] would denote a piece that can move as a dabbaba, or twice as a king.

Another extension is that inequalities can be used in place of numbers denoting range: thus, while R4 is a piece that moves like a rook, but only up to four squares, R(2≤n≤4) is a piece that moves like a rook, but only two, three, or four squares. Further, pn refers to cannon-like pieces that can jump at most n pieces along their path, and pp means the same as p∞ (just as WW is synonymous with W∞, both meaning a rook). Finally, x stands for "shooting": the xK for instance can pass its turn (shooting empty squares), or it can shoot (capture) any adjacent enemy piece without moving.

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. (However, evidence from historical chu shogi mating problems suggests that this prohibition does not apply to a player who is in check.) 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.

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. This would presumably imply that checkmate and stalemate both lead to wins for the checkmating or stalemating player.

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.)

According to the German Chu Shogi Association, the average values of the pieces are (using the interpretations of the English-language sources):

These average values do not take into account the special status of the king and prince as royal pieces. They have also been normalized so that the pawn is worth 1 point to avoid fractions. Additionally, pieces gain in value if they have a good chance of promotion (particularly for the water buffalo, which promotes to the most powerful piece in the game), and the jumping generals and fire demon tend to lose some power as the board empties (because they then cannot make full use of their jumping and burning abilities).