Xiangqi originated in China and is one of the most played games on earth; in Vietnam it is known as Cờ Tướng and has its own strong tournament tradition. Pieces sit on the intersections, a river splits the board, and cannons must jump a screen to capture.
Variant implemented
Standard Xiangqi rules: 9×10 lines, river, palace, cannon screen-capture, flying-general prohibition, perpetual-check restrictions simplified to a repetition draw.
Board and pieces
Nine files by ten ranks, with pieces on the intersections. A river divides the halves and each side has a 3×3 palace.
Setup
Back rank: chariot, horse, elephant, advisor, general, advisor, elephant, horse, chariot. Cannons on the third rank. Five soldiers on the fourth.
Turn
Move one piece according to its type.
Capture and scoring
Move onto an enemy piece to take it. The cannon is the exception: it moves like a chariot but must jump exactly one intervening piece — a "screen" — to capture.
Win condition
Checkmate the enemy general. Stalemate is also a loss.
Draw condition
Repetition is scored as a draw.
Special rules
The general never leaves its palace. Advisors move one step diagonally, inside the palace only. Elephants leap two diagonally, are blocked by the midpoint, and may never cross the river. Horses leap (1,2) and are "hobbled" if the orthogonally adjacent point is occupied. Soldiers move forward only, gaining sideways movement after crossing the river. The two generals may never face each other down an open file.
Computer opponent
Alpha-beta with capture ordering. The evaluation weights material, open files for chariots and soldiers that have crossed the river.