Rainbow mate

A rainbow mate uses all four of the attacker's minor pieces, meaning both bishops and both knights. They form a curved arrangement around the king's area, which gives the pattern its name.

In the typical form, the bishops stand next to one another and each is protected by a knight. Either a bishop or a knight may give the final check, but all four pieces contribute by checking, protecting the mating piece, or covering escape squares.

This is a very rare pattern and should not be identified merely because four minor pieces are present. Test their functions: mentally remove each piece and see whether a defense appears. If one piece has no role, the full pattern is probably absent. Its coordination combines ideas also seen in double bishop mate, built on diagonals, and double knight mate, built on jumps that cover exits.