Home * Games * Chinese Chess * Jeiqi
Jeiqi board, with pieces in their starting positions 1
Jeiqi (in Chinese: 揭棋, in Vietnamese: Cờ Úp, probably other names in English: uncovering / dark / unveiling chess/xiangqi) is a Xiangqi (Chinese chess) variant that is rising star when the number of players grows rapidly, especially in China and Vietnam.
Basically, the game is played with a typical Xiangqi board and pieces. The rules and the object are similar too. The main differences are:
- At the starting point excepting the King, all 15 pieces of each side will be covered (usually by small plastic covers or simply put them face down to hide their symbols) and randomly put on original positions. Those covered pieces are called Jeiqi, or dark or covered ones
- A Jeiqi piece should do the first move as the original piece in which it is located. For example, the covered piece on the bottom left corner (which is a Rook position in Xiangqi) must do the first move as a Rook. That is why covered pieces are also called “fake” based on the original pieces' locations they are on. For example, the mentioned covered piece (on the bottom left corner) is called "fake Rook". After the first move, it will be revealed/uncovered to show its real material (for example, the fake Rook revealed to be a Pawn). From now on, that (unveiled) piece will move as its real chess type (for example, the new Pawn will move as a Pawn). The revealing is similar to chess promotion, but in this case, players cannot control which new types the pieces can become. We call it “revelation” to distinguish it from promotion
- Revealed Advisors and Elephants can move freely without any limitation by area, as they were in Xiangqi. It means they can appear out of palaces and can cross the river to attack the opposite Kings
- Kings are still limited in palaces, Pawns could be revealed anywhere, but can go ahead only when they are still in their homeland and can go sideways after crossing the river
- Capture: covered pieces could capture or be captured as usual. However, after being captured, they may remain in covered status; no one knows which real materials the captured covered pieces are
Contents
Pieces
Pieces are similar to Xiangqi except they have extra covered pieces.
Images |
Name |
Notation 1 |
Movement |
|
|---|---|---|---|---|
|
暗子 |
Covered piece |
X |
moves and captures |
Jeiqi Notation
Jeiqi reuses FEN, and the Xiangqi move notations, with small, backward-compatible additions for the covered (dark) pieces and for the material that has already left the board. A position with no covered pieces and no captures is written exactly as the equivalent Xiangqi position, so a plain Xiangqi reader can still parse it.
Piece letters
Pieces use the WXF / Wikipedia Xiangqi letters. Uppercase is White (Red); lowercase is Black:
| Letter | Piece |
|---|---|
| K, k | General (King) |
| A, a | Advisor |
| E, e | Elephant |
| R, r | Chariot (Rook) |
| C, c | Cannon |
| H, h | Horse |
| P, p | Pawn |
| X, x | Covered (dark) piece — true type hidden |
X / x is the only letter Jeiqi adds. A covered piece's owner and square are known; its real type is not.
FEN
Six space-separated fields, as in Xiangqi:
- Piece placement — ten ranks from Black's back rank down to White's, files a–i; digits count contiguous empty points;
/separates ranks. A covered piece is written X (White) or x (Black). Directly after the placement, with no space, an optional bracketed captured-pieces group may follow (see below). - Active color —
worb. - Castling — unused; always
-. - En passant — unused; always
-. - Halfmove clock — halfmoves since the last capture or pawn move. A reveal does not by itself reset the clock; only a capture or pawn move does. (Jeiqi/Xiangqi draw rules differ from the chess fifty-move rule.)
- Fullmove number — as in chess.
Captured pieces
The pieces that have left the board are listed in brackets [...] appended to the placement field with no separating space — the same position Crazyhouse / Bughouse FEN keeps its holdings, rather than overloading the (unused) castling field:
- Content. Every captured piece is written by its true type, as a letter immediately followed by its count (a decimal number), e.g.
P2,r1. Case denotes the side that lost the piece (uppercase = White, lowercase = Black). A captured piece's identity is always known: it was either already revealed, or it is revealed at the moment of capture. - Covered pieces are not listed. The multiset of still-covered pieces is fully derivable from the starting material minus what is revealed on the board minus what has been captured. Storing X / x here would be redundant, could drift out of sync with the board, and would force two-digit counts (a side can hold up to 15 covered pieces).
- Omit empty brackets. With no captures the group is dropped entirely, so the FEN is byte-identical to the plain Xiangqi FEN of the same position.
- Canonical order. White entries first (uppercase), then Black (lowercase); within each color the WXF order A E R C H P (the General is never captured). Readers should accept any order on input and emit this canonical order on output, so equal positions always produce identical strings.
Examples
Initial position. Every piece is covered except the two Generals, and nothing has been captured, so the brackets are omitted:
xxxxkxxxx/9/1x5x1/x1x1x1x1x/9/9/X1X1X1X1X/1X5X1/9/XXXXKXXXX w - - 0 1
A midgame position, Black to move, with both revealed and covered pieces on the board and material in hand:
x3k3x/c3e4/4R4/E4r2x/4p4/4A1R1P/3A5/6E2/9/3XKX2X[C2H1P2a2r1c1h2p1] b - - 0 1
The board still carries covered pieces (X on White's back rank, x in the corners) alongside revealed ones. The brackets read: White has lost 2 Cannons, 1 Horse and 2 Pawns; Black has lost 2 Advisors, 1 Chariot, 1 Cannon, 2 Horses and 1 Pawn. No covered piece appears in the brackets.
Move notation
A covered piece moves, on its first move, as the piece whose start point it occupies (its "fake" type); that move reveals its true type, after which it moves as the revealed type. Revealing is like promotion, except the new type is fixed by the piece rather than chosen by the player.
The reveal is recorded in the move:
- Long algebraic / UCI. Append the revealed type as a lowercase letter to the from–to move when — and only when — the move reveals a piece:
b9c7c(a covered piece on the Horse point plays b9–c7 and is revealed as a Cannon),h2h7r(revealed as a Chariot),i9h9p(revealed as a Pawn),e3e4e(revealed as an Elephant). An ordinary move of an already-revealed piece carries no suffix:e4g2. - WXF / relative. Name the moving piece by its fake (start-point) type and append
=and the revealed type:r9.1=cmeans the covered piece on the Chariot point at file 9 advances one rank and is revealed as a Cannon.
Name the fake piece, not X. Writing the move with X is ambiguous: x9.1=c does not say whether a covered Pawn or a covered Chariot on file 9 moved, whereas r9.1=c is unambiguous. A reveal is easy to detect — a piece is revealing exactly when the type it now is differs from the fake (start-point) type it moved as; an already-revealed Chariot on file 9 simply plays r9.1 with no =.
Forum Posts
2015 ...
- A proposal for Jeiqi notation by Nguyen Pham, CCC, December 26, 2018