Seirawan Chess

The opening position for Seirawan.

Rules

Seirawan is played on a 8x8 board White moves first. White and black begin the game with 2 Knights (N)
White and black begin the game with 2 Bishops (B)
White and black begin the game with 2 Rooks (R)
White and black begin the game with 1 Queen (Q)
White and black begin the game with 1 Hawk (H) in-hand
White and black begin the game with 1 Elephant (E) in-hand
White and black begin the game with 1 King (K)
The King is a royal piece (king). White and black begin the game with 8 Pawns (P)

Objectives

The game is won:

• If the enemy king is check-mated.

The game is a draw:

• If the enemy king is stale-mated.
• If the enemy only has a king left and cannot take your last piece
• If the same position occurs for the third time.
• If no progress has been made for 50 consecutive moves.
• If there is insufficient material to mate the enemy king.

Movement of the pieces

Knight (N)
The Knight moves and captures as a leaper (marked •). Betza description: N
Bishop (B)
The Bishop moves and captures as a slider (marked •). Betza description: B
Rook (R)
The Rook moves and captures as a slider (marked •). Betza description: R
Queen (Q)
The Queen moves and captures as a slider (marked •). Betza description: Q
Hawk (H)
The Hawk moves and captures as a compound (marked •). Betza description: BN
Elephant (E)
The Elephant moves and captures as a compound (marked •). Betza description: RN
King (K)
The King moves and captures as a leaper (marked •). Betza description: KisO2 The King can castle.
Pawn (P)
The Pawn moves as a stepper (marked •). The Pawn captures as a stepper (marked ×). Betza description: fmWfceFifmW2 The Pawn cannot move back to the square it came from. The Pawn can capture en-passant. The Pawn can promote to a Knight, Bishop, Rook, Queen, Hawk or Elephant.

Initially, the Hawk and Elephant are not on the board. Players may introduce the Hawk or Elephant when they move a piece from the back rank for the first time. The Hawk or Elephant appears on the location the other piece just vacated. This move is called gating. If all back-rank pieces have moved, the Hawk or Elephant can no be gated anymore. Gating is only allowed if the piece-move would be legal without introducing the gated piece. If the piece is pinned and could not normally move, the move is not allowed (even though the gated Hawk or Elephant would block the pin). Pieces can be gated when castling (on the Rook or King square), but only one piece can be gated.

Promotion

Pawn (P)
The Pawn must promote when it reaches one of the squares marked with •. The Pawn can promote to a Knight, Bishop, Rook, Queen, Hawk or Elephant.