Quick answer
Cờ úp is Vietnamese hidden Xiangqi on a 9×10 board. The two generals are visible and 30 pieces start covered. A covered piece first moves as its starting-square role, then reveals its identity. This is different from Banqi on a half board. This guide covers Vietnamese hidden chess · ChessPlayX conventions. Check the movement, capture and game-ending rules below before applying rules from another variant.
- Players
- 2
- Board
- 9 × 10 points
- First move
- Red moves first.
- Pieces per player
- 16
Ruleset and sources: Vietnamese hidden chess · ChessPlayX conventions
How is the board set up?
Use the Xiangqi starting formation with two visible generals. Each side's other fifteen pieces are shuffled face down. A covered piece's starting location determines its movement until its first reveal.
How do the pieces move?
Before revelation, a hidden piece follows its starting role. The moves below apply after it is revealed; advisors and elephants have wider freedom than in ordinary Xiangqi.
Reveal a piece
A hidden piece first moves as the role at its starting square. It is revealed after that move and then follows its real role. A captured hidden piece remains secret in the public record.
How does a covered piece get revealed?
Move by its starting square
Choose a covered piece and make a legal move for the role of its starting square, including a capture. A covered cannon still needs exactly one screen to capture.
Flip on arrival
As soon as the move ends, the piece turns face up and both players see its real identity.
Play its real role
From your next turn, the piece moves and captures as its real piece. It never goes back to the role of its starting square.
What rules do covered pieces follow?
Until it is revealed, a covered piece counts as the piece of its starting square, with every ordinary Xiangqi limit.
Ordinary limits before the reveal
A covered advisor stays in the palace, a covered elephant cannot cross the river and is blocked at its eye, a covered horse is blocked at its leg, and a covered soldier only steps forward.
Check follows the starting role
Covered pieces attack and give check as the piece of their starting square, not as their hidden identity. Whether a move leaves your general in check is judged the same way.
Captured covered pieces stay secret
When a covered piece is captured, ChessPlayX never reveals it to either player or to spectators. The public record shows only a covered piece.
A revealed soldier is still a soldier
A piece revealed as a soldier steps forward only until it crosses the river, then may also step sideways, wherever on the board it was revealed.
When does the game end?
Checkmate or having no legal move loses. ChessPlayX draws on the third occurrence of the same public position with the same side to move, or after 120 consecutive individual moves without a capture, soldier move or reveal. Any capture, soldier move or reveal resets that count. Hidden chess uses this convention, not orthodox Xiangqi's WXF chase adjudication. Perpetual check and perpetual chase are not penalised: a repeated position simply draws on its third occurrence.
How to play on this screen
On desktop
Click one of your pieces, then a highlighted legal destination. A covered piece makes its first move as the role at its starting point; its identity appears after that move. A piece captured while still covered stays hidden in the captured list and replay.
On a phone
Tap a piece, then a highlighted destination; dragging is not required. If a move-choice window opens, select one of its legal options. Use “History” below the board to review moves, “More” for game information, and the three-dot menu in the header for game options. Return to the current position before playing the next move.
What should beginners watch for?
Do not assume a covered piece has the identity of its starting square. After revealing it, check its actual movement before planning the next turn.
Frequently asked questions
Is a cover on a chariot square more likely to hide a chariot?
No. All fifteen pieces are shuffled at random, so every cover starts with the same odds: 2/15 each for a chariot, cannon, horse, advisor or elephant, and 5/15 for a soldier. The square only decides the first move.
When is a covered piece revealed?
Right after its first move, whether or not that move captures. From the following turn it moves as its real piece.
Can a revealed advisor leave the palace?
Yes. Once revealed, an advisor moves one point diagonally anywhere on the board, and an elephant moves two points diagonally and may cross the river, though a piece on its eye still blocks it. The general always stays in the palace.
What happens to a covered piece that is captured?
It leaves the board unrevealed. On ChessPlayX neither player nor any spectator learns its identity, so count it as unknown when you estimate which pieces remain.
Can a covered piece give check?
Yes. It threatens points as the piece of its starting square. For example, a covered cannon with exactly one screen between it and the enemy general gives check.
When is a hidden chess game drawn?
When the same public position occurs for the third time with the same side to move, or after 60 moves by each side without a capture, soldier move or reveal. Checkmate or having no legal move loses.
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Sources and rule verification
- Ruleset covered
- Vietnamese hidden chess · ChessPlayX conventions
- ChessPlayX — online rules published on this page
This guide describes play on ChessPlayX. Platform-specific conventions are stated in the relevant sections; tournament administration may differ.
A separate rule-review date is not recorded for this guide. The update date is not a verification date.