The Game of Y, by Kadon

The Game of Y is a simple positional game, with much of the appeal of Go - players take turns placing stones on a triangular board, attempting to join all three sides together with a chain of their stones. There are no captures in the game, so the strategy is similar to that of Twixt - place stones so that they can be connected in more than one way, then concentrate on other areas of the board until your opponent threatens to disrupt your chain.

It seems almost a shame to say so little about The Game of Y, but there is little more that needs to be said; the rules are elegantly simple but, like go, this is a very deep game.

Kadon produce two versions of this game - The Game of Y itself, with Go stones and a gorgeous triangular wooden board, plus a book called "Mudcrack Y", full of different layouts for the game, to be played with pen and paper.