Ghost King Chess

In the historic Japanese variant Maka Dai Dai Shogi the King could promote to an ominipotent Emperor. This piece could move or capture to any square on the board, with as only exception that it could not capture the opponent's royal piece when that was protected.

The variant described here was designed for trying how an omnipotent royal piece would work in a FIDE context. The logical name would be Emperor Chess, but since that name was already taken, I renamed the Emperor to 'Ghost King'.

Setup

The setup is that of orthodox Chess, with the understanding that the King is replaced by a Ghost King.

Pieces

The Ghost King moves like a Universal Leaper (aka Kraken): it can teleport to any square on the board that is empty, or contains an enemy piece (which is then captured). Staying where it was never counts as a move, though. (So you cannot pass your turn!)

Other pieces move as in orthodox Chess.

Rules

The game is won by capturing the opponent's Ghost King, with the restriction that you cannot do this with your own Ghost King if that exposes the latter to capture.

There is no restriction on exposing your Ghost King to capture on other moves. (Doing so will of course lose you the game, but it means stalemate does not exist.)

Otherwise FIDE rules apply.

Notes

Leaving your Ghost King unprotected loses immediately, as the opponent's Ghost King can then take it. So although it is always legal for a Ghost King to capture any non-royal opponent piece, it would be suicidal if you have no second attacker on that piece, which would protect your Ghost King afterwards. Of course such a second attacker would not help you if there were non-royal pieces protecting the potential victim; these could capture your Ghost King anyway.

The tactical effects of the omnipotence is thus not as large as we might have imagined. On rare occasions the Ghost King can be used to capture an opponent, if the other attackers are somehow tied up (e.g. because these were pinned, or must keep protecting some other piece).

Checkmating the Ghost King in the middle-game is almost impossible. Victory must be achieved by eliminating the pieces that could keep it protected, so that the number of squares where it could be protected becomes small enough so that they can all be kept under attack.

Last revised by H. G. Muller.