Seal the palace
Seal the palace. Xiangqi (Chinese chess), Red to play. Study 1 reference ply, try both sides and branch from the replay.
Site coordinates run A–I left to right and 1–10 top to bottom; A1 is the top-left intersection.
Why the finish works
Compare the finish and the defensive replies
One chariot checks; the other closes the door
Play A3–A1. Its path is clear. From A1, the chariot checks along the first rank and covers both D1 and F1. Moving sideways therefore does not save Black’s general.
E2 is covered by the other chariot, still on I2. Its line to E2 is unobstructed. Black has no other piece to interpose or capture the checking chariot, and the general cannot jump from E1 to A1. All three adjacent escapes are now accounted for. The useful cooperation is the division of duties: one chariot checks while the other maintains the barrier.
A tempting check that fails
Reset and try I2–I1 instead. This also checks along the first rank, preventing D1 and F1. However, moving that chariot abandons the second rank. The chariot on A3 does not attack E2.
Black can now reply E1–E2. That square is inside the palace, neither chariot attacks it, and the soldier on E6 still prevents the generals from facing. I2–I1 is therefore a check but not mate in one. Whenever you move a piece that was containing the opponent, ask which square loses protection. Checking moves must be evaluated after the move, not on the old board.
Read the position, one decision at a time
Try the position first, then open the notes. They explain measurable changes in the reference, not every possible variation.
Reveal step-by-step explanations
1. Red chariot · A3 → A1
The destination was empty. The opposing general is in check and has no legal reply: this position is checkmate. Before this move the same piece had 17 legal destinations; other legal moves are not thereby proved equally strong.
Understand this position
10 ranks × 9 files · 4 red pieces · 1 black pieces
Before moving, locate both generals and check open files, cannon screens and blocked horse legs. Try a legal move on the board, then examine the reply rather than assuming the first check wins. The reference is one continuation to compare, not an evaluation of every possible branch.
Read the reference line (1 plies)
Coordinates match this board: letters left to right, row numbers from top to bottom. These are board coordinates, not traditional score notation.
- Red chariot
A3 → A1