[1] Captured pieces are not eliminated from the game but can reenter active play through drops, similar to shogi.
In exchange, the player returns a previously captured enemy piece which the opponent may drop on a future turn.
Instead of making a normal move, a player can perform a hostage exchange to "rescue" a man held prisoner by the opponent and drop the freed man back into play on the board onto an open square.
On any turn, instead of making a normal move, a player can drop a man from his airfield into active play on the board.
A hostage exchange is performed by transferring a piece from one's prison to the opponent's airfield, then selecting and releasing a piece from the opponent's prison and immediately dropping it onto an empty square on the board.
A drop can occur as part of a hostage exchange, or directly from a player's airfield.
If the promoted piece is subsequently captured, it retains the type that it had when entering prison.
So, if a pawn is on its player's 7th rank with no available piece to promote to: According to David Pritchard:[4] Hostage Chess, for want of a better description, is a Chessgi variant.
And secondly it introduces additional skill elements that are difficult to evaluate, which in my view make the game much more interesting.Standard notation is used with some extensions: White: Frank Parr Black: David Pritchard Casual game[7][8] 1. d4 d5 2. c4 2... dxc4 3.