Piececlopedia: Alibaba

Historical notes

The Alibaba is used in some fairy chess problems. It combines the movement of two other fairy pieces: the Alfil and the Dabbabah. Its name is a combination of these two names, as well as the name of a character from the Arabian Nights.

This piece has been used by Fergus Duniho in Interdependent Chess, where it is called a Spider. The movement of this piece resembles the eight legs of a spider.

Movement

The Alibaba leaps exactly two spaces in any radial direction, i.e. in any diagonal or orthogonal direction. If any piece stands between an Alibaba and its destination, it just leaps over it as though it weren't there.

Movement diagram

In the diagram below, the alibaba can jump to all the squares marked with a white circle.

Vocabulary: Radial

The Alibaba moves only in radial directions. A radial direction is any diagonal or orthogonal direction. Radial movement moves along the natural contours of the chessboard. If you draw a line between the midpoint of the space a piece moves from and the midpoint of the space it moves to, that line will pass through the midpoint of every space it crosses--so long as it was a radial move. But if it was an oblique move, which is the opposite of radial, the line will not pass through the midpoint of every space it crosses. And if you drew lines from the midpoint of each of these spaces to the starting space, they would be at different angles. Of course, all of this presumes that spaces are symetrical in shape, identical in size and shape, and naturally fit together in rows. This all applies to regular square or hexagonal chessboards, though it might break down with very odd chessboards.

Checkmating

Its severely limited board access makes the Alibaba a very weak piece, but together with a strong minor it might still be able to force checkmate on a bare King. A compound of a Knight and a Wazir (sometimes called Marquis) appears to be sufficient. Try it!

A minor that itself is proficient at delivering mate in all corners does not need to be exceptionally strong when assisted by a Alibaba. Try it!

In combination with a color-bound piece on even-sized boards there will always be one corner that neither piece can attack, so that the game will end as a fortress draw if the bare King can reach that corner.

Images

Click on an image to view the full piece set it belongs to.

Alfil + Dabbabah

Spider