Cooperative chess

Cooperative chess includes chess variants that feature interpersonal cooperation rather than competition. In such variants, two players play the game on either a classic or modified chess board, with each player striving to achieve a mutual rather than solo victory.
Variants.
Two cooperative chess variants that encourage cooperative rather than competitive play are Hans Theo Frenkel's "Metapontum" and Aaron Lundstrom's "DUO: Cooperative Chess for Communities".