Here is a variant played on an 11 by 11 board, which was at one time a popular size for Chess variants with a military theme.
In the front row, each player has six checkers, moving as described above, and five spaceships, as follows:
Ch Sp Ch Sp Ch Sp Ch Sp Ch Sp Ch
Each spaceship has a definite orientation, which can be in any of the eight orthogonal or diagonal directions. Its orientation determines its possible moves, as shown below:
A spaceship moves in the direction in which it is pointed up to three squares orthogonally, and up to two squares diagonally. It may also be rotated by 45 degrees, and then move, but in that case it moves one fewer space in the new direction.
When capturing, as befits a spaceship, it is considered to blast the piece which it is capturing with its ray guns. As a result, the rule for capturing is as follows: a piece may be captured if it is on a square to which the spaceship can move, but the spaceship is to move towards that square, but stop one square short of it.
A spaceship can therefore capture a piece on an adjacent square in either the direction in which it is pointing, or one of the directions 45 degrees on either side of that direction, without being moved, but with being rotated, if necessary to have it point towards the captured piece.
There is one additional rule, to deal with the case of spaceships that reach the edge of the board and cannot move. It is possible to turn a spaceship 45 degrees, without moving it, and without making a capture, if after that move is made, the player who does so also then moves another piece which is not a spaceship. This deals with the issue without promoting spaceships, giving them a backwards move, or eliminating the possibility of Zugzwang from the game.
The second rank is a line of pawns.
On the back rank, the pieces are:
Rook, Tiger, Camel, Knight, Bishop, Queen, King, Bishop, Knight, Camel, Rook
The Tiger moves without capturing like a Bishop, and makes captures only like a Knight. Note that the Tiger is on a white square, so it initially only attacks black squares, which are also the squares on which all the checkers are located.
The Camel, which makes a leaping move similar to that of the Knight, but with a displacement of three spaces in one orthogonal direction, and one space in a perpendicular direction, thus remaining on the same color of square, is the remaining unusual piece in this game.
An alternative form of this game may be played with the Queen's Rook replaced by a Cannon. The Cannon moves like a Rook, but when capturing, it captures the second piece on any orthogonal line, jumping over the first piece. In this case, Queen's side Castling still takes place normally, with the Cannon acting as if it were a rook.