When a Key is not good

The Key of the solution of a chess problem is considered (in our times) that is not good when is true anything of the following:

>> If the key is obvious.

>> If there is no defense of the White for a certain check of the Black, this is called unprovided check and, since it must be stopped, it reveals the key.

>> If there are not set mates for certain flights of the black king in a two-mover, then the key becomes obvious.

>> If the key takes a piece of the opponent.

Capturing a piece is very fierce and aggressive key and is not good. (If we see such a key in an orthodox problem, it will have probably humorous content). Capturing a pawn is tolerated if the problem is generally interesting.

For heterodox problems this condition is not valid. For example, it is quite acceptable in a Helpmate problem to have a capturing key.

>> If the key is check.

The problem-with-checking-key was common in previous centuries, but today it is not desirable. It can be accepted only if it is impossible to compose a problem-without-checking-key showing the same Theme or the same Task. For heterodox problems this condition is not valid. For example, it is quite acceptable in a Helpmate problem to have a checking key.

>> If the key does not allow the opponent to give check.

>> If the key limits the mobility of the black king (in orthodox problems).