Glossary of Chess Problems - C

C

Clearance

In general, the movement of one piece so that another can move to a particular square. In square vacation the first piece moves so that the second can occupy the square on which it stood; in line vacation the first piece moves so that the second can pass over the square on which is stood on the way to its destination; line clearance, also known as the Bristol, is a particular type of line vacation in which a piece moves along a line so that another piece can move a shorter distance behind it along the same line.

Composition

A constructed position (as opposed to a position found in a game) serving as a Chess problem.

Cook

A second key move, unintended by the composer. A cook is a serious flaw, and invalidates a problem. The publication of cooked problems was once common, but in the modern era computers can be used to check for cooks, and cooked problems are rarely published.

Cylindrical board

A board in which the a and h-files are considered to be connected (a "vertical cylinder") or the first and eighth ranks are connected (a "horizontal cylinder"). A combination of the vertical and horizontal cylinders is called an "anchor ring".