Rogue Elephant is based on my disappointment with my other variant Zaibatsu Chess. Zaibatsu Chess did what I was looking for in terms of a more European version of Shogi (the Japanese cousin of Chess). All the pieces could promote, and captured pieces changed side and could be dropped on the board. However, to make all pieces promotable, I had to add several high powered pieces to the game. Even though I like some higher powered Chess variants like Seirawan Chess, I think Zaibatsu Chess goes a bit too far. So I was looking for a way to power down Zaibatsu Chess.

Then I started to play Crazy Elephant. Crazy Elephant is a variant of Crazy House proposed by Thomas Meehan. In Crazy House captured pieces change sides and can be dropped on the board. However, where Crazy House uses Chess as the basis for the game, Crazy Elephant uses Shatranj as the basis. Shatranj is the Persian predecesor of Chess. It is a lower power game than Chess. Indeed, it's low power and slow start are what drove a lot of the changes that turned it into modern Chess. So I thought that if I added promotion of all the pieces to Crazy Elephant, I might get a lower powered Zaibatsu Chess.

For those unfamiliar with Shatranj, it is very much like Chess, but with the following differences:

 * There is no castling.
 * The pawn cannot move two forward on it's first move.
 * The bishop is an elephant, which leaps two squares diagonally.
 * The queen is a counsellor, and can only move one square diagonally.
 * Pawns can only promote to counsellors.
 
When pieces reach the seventh or eighth rank they promote (except for the king, which cannot promote). When a piece promotes, it retains the moves it has before, and gains the moves of the counsellor in addition. That is, each piece gains the ability to move one square diagonally in any direction. The exception is (obviously) the counsellor, which promotes to a bishop. When promoted pieces are captured and change sides, they demote back to their original piece type. Also, dropping a piece on the 7th or 8th rank does not allow it to promote.

To be clear, here are the pieces of Rogue Elephant and how they move and promote:

Pawn: a pawn may move one square straight forward without capturing, or one square diagonally forward to capture. A pawn promotes to a captain, which can move one square in any diagonal direction (capturing or not capturing), or one square straight forward without capturing.

Knight: a knight may move one square orthogonally and then one square diagonally in the same direction. This move may not be blocked by intervening pieces. A knight promotes to a charger, which can make a knight's leap and can also move one square diagonally in any direction.

Elephant: an elephant may move exactly two squares diagonally in any direction. This move may not be be blocked by intervening pieces. An elephant promotes to a mastadon, which can make an elephant's leap and can also move one square diagonally in any direction.

Counsellor: a counsellor may move one square in any diagonal direction. A counsellor promotes to a bishop, which can move any number of squares in any diagonal direction. This move can be blocked by intervening pieces.

Rook: a rook may move any number of squares in any orthogonal direction. This move can be blocked by intervening pieces. A rook promotes to a dragon, which may move any numbers of squares in any orthogonal direction, and may move one square in any diagonal direction.

King: the king may move one square in any direction. The king may not promote.