Ice Age Chess is an original variant by Köksal Karakus. It introduces a new element - an ice cube - which works as an obstacle and pieces (except knights) cannot pass through it.
Start position and game object
The positions of pieces are the same as in classic Chess. The only difference is the rest of board squares - the blank spaces are filled with ice cubes:
The object of the game is to checkmate opponent's king or make it frozen. This special rule will be explained in the next sections.
How to make moves
Ice Age Chess follows the standard Chess rules for piece movement, capturing, checks etc. The blocking ice cubes can be captured as any other pieces and by both white and black player. Since the game starts with no blank spaces to move to, the first move must be a capturing one. The following picture shows the board after the first move of both players - white H2 pawn captured the G3 ice cube and black G8 knight captured the F6 ice cube:
Other important rules
After every 20th move of the black player (20th, 40th, 60th etc.) the Ice Age comes. This event fills all empty squares (except those which are orthogonally surrounded by pieces of any color from all sides) with ice cubes.
If the Ice Age surrounds an isolated piece (it is not adjacent to any other piece in any direction), this piece is frozen, removed from the board and another ice cube is placed to its position. The next picture shows a situation after black player's 20th move (before and after the Ice Age event):
As you can see, the isolated black rook on H8 has been frozen and all other pieces survived. All empty squares except F1, F6 and E7 (which are fully surrounded by pieces horizontally and vertically) were filled with ice cubes.
If the Ice Age freezes a king, the player who is its owner loses the game. If both kings are frozen at the same time, the game is a draw.