Packaged Variants

This is a list of variants that are packaged in the main repository and are available in the online version of the game.

You can enable any combination of these variants in the game by checking the appropriate boxes in the "Options" section of the "New Game" screen.

Variant	Description
Chess960	Chess960, as described here.
Knooks	Rooks and knights of the same player can be moved to the same position and merge into a Knook: a piece that moves both like a rook and a knight (but cannot castle).
Forced En Passant	En passant capture is mandatory if available. If a player is checked and can en passant, they lose. A player can move into a position that will put their king under attack if the next player must en passant instead of taking the king.
Knight Boosting	When a pawn is promoted to a knight, the player gets an extra turn to move that knight.
Omnipotent F6 Pawn	When there is an enemy piece on F6, a pawn can be summoned there.
Siberian Swipe	When a Rook hasn't moved yet, it can jump over all pieces in a file to capture an enemy opponent's rook.
Il Vaticano	When 2 bishops of the same player have a 2-square gap between them, and that gap is filled by 2 enemy pieces, the bishops can switch places, capturing both enemy pieces.
Beta Decay	When a queen has an empty, straight, line of 3 or more squares with a board edge, hole, or a piece of the same player - it can split to a rook, bishop, and pawn - in that order.
La Bastarda	When a queen is moved to an enemy king, the king can move away directly opposite from the queen, summoning a pawn of the same player as the queen between them.
King Cant Move to C2	Kings cannot move to C2.
Vertical Castling	Castlling can also be done vertically.
Double Check To Win	In addition to checkmating, a player can win by giving check with 2 pieces or more.
Capture All Pieces To Win	Instead of checkmating, a player can win by capturing all pieces of the opponent. Kings can be under attack and can be taken.
Duck Chess	There is a Duck on the board which can not capture or be captured, but can move to any position. After playing a turn, the player has to move duck to a different square. There are no checks, and you lose by getting your King captured.