Jos

JOS is a two-player puzzle game released as freeware in 1998 by the Finnish outfit Haglund Studios — by its own account the studio's first and only puzzle title. The idea recalls the classic game of Nim: fifteen blocks appear on the screen and the two players take turns removing them.

The goal is to remove blocks cleverly enough that the very last one is left for your opponent — whoever is forced to take the final block loses. It is a battle of simple mathematical strategy rather than reflexes, best enjoyed as a quick duel between two people sharing one keyboard.

The game is a small artefact of the late-1990s Finnish homebrew and BBS scene, the kind of title big retro sites never list. It runs right in your browser on OldGame.cz.