Board and setup
The board is 7 files (a to g) by 8 ranks, with a river between ranks 4 and 5. Each side has a 3 by 3 palace, but the two palaces sit in opposite corners: Red holds the bottom left (a1 to c3) and Black holds the top right (e6 to g8). The whole setup has 180 degree rotational symmetry.
Red moves first. This is open information: both players see the whole board and both reserves.
The pieces
The Chariot, Cannon, Horse, Elephant, Advisor, and General move as they do in xiangqi. The Soldier is the one standard piece with a changed move, and the Treasure is new. In the diagrams below, a green dot marks a quiet destination, a green ring marks a capture, and a red cross marks a point the piece cannot reach.
Chariot: slides any distance orthogonally, the strongest piece on the board. Here it can take the soldier on d7.
Cannon: moves like the Chariot on open lines, but captures only by jumping exactly one screen piece, friend or enemy. On the right, the cannon on d2 takes the chariot on d7 over its own soldier screen.
Horse: steps one point orthogonally, then one point diagonally outward. If the orthogonal step is occupied, that whole direction is blocked. On the right, the soldier on d5 takes away both forward destinations.
Elephant: moves exactly two points diagonally, is blocked by an occupied midpoint (the elephant eye), and can never cross the river.
Advisor: moves one point diagonally and stays inside the palace.
General: moves one point orthogonally and stays inside the palace. One xiangqi rule retires itself here: because the palaces sit in opposite corners, the two generals never share a file, so the facing-generals rule never comes into play.
Soldier: moves one point forward, never backward. Once it crosses the river it may also step one point sideways, exactly as in xiangqi. The Treasure is the other piece the river holds back: it never crosses at all.
Treasure: the one new piece. It steps one point in any of the eight directions and never promotes. It roams its own half freely, but it never crosses the river, moving or dropping. It is the piece you are storming for, and it stays in the fortress.
There are no promotions. The river matters three ways: the Soldier gains its sideways step by crossing it, and neither the Elephant nor the Treasure may cross it at all.
Capture, hold, drop
When you capture any piece other than the General, it changes to your color and enters your reserve. Both reserves are open information, have no size limit, and keep pieces for as long as needed. On your turn, either move a piece on the board or drop one piece from your reserve onto an empty point. Generals are never captured or held in reserve.
Chariots, Horses, Cannons, and Soldiers may drop on any empty point. Advisors, Elephants, and Treasures keep their normal territory restrictions.
A dropped piece is live immediately. A drop may give check or deliver checkmate, and a Soldier dropped past the river arrives with its sideways step already earned. The one limit is the usual one: no move, drop included, may leave your own general in check.
How games end
Checkmate wins. A player with no legal move also loses, even when not in check. There is no fifty-move or no-progress draw.
On the third occurrence of the same position, a player who gave check on every one of their moves in the repeating cycle loses. If neither player was the sole perpetual checker, the repetition is drawn.
Games can also end by timeout, resignation, or abandonment.
A sample game
This engine game shows both new rules at work. Three soldiers cross the river and gain their sideways step, and on move 23 Red drops its captured Treasure on d1, back inside its own half, because that is the only half it may enter.
This game was chosen from twenty engine games played the same way. All twenty are in the companion study, one chapter each, with a note on where the engine’s evaluation says the game turned.
Play on Mistboard
A piece you capture changes to your color and goes into your reserve, ready to drop back in. No account needed.