The object is to form a line of four, either diagonally or orthogonally. Stalemate is loss. Players have nine stones each. The board is 5 x 5. White moves first.
Players first drop a stone each. Then they take turns to make make double-moves. First, the player slides a stone, diagonally or orthogonally. (A slide move must be longer than one step.) After the slide move, the player must drop a stone on the last square slided over. The first stone moved is called “forerunner”. The second is called “follower”.
In the opening phase, the second player may forfeit his first slide move and make only the drop move. (This is the only time that pass is allowed and serves to equalize chances.) When all nine stones have been dropped, you must instead relocate any of your stones on the board (except the one just moved) to the last square slided over.
Delta is a fast game, so it is usually played several times. The player with the highest score wins. In the end position, the winner gets as many points as there are empty squares. Win by stalemate gives 1 point. Delta was invented by Swiss chess problem composer Erich Brunner.
‘Delta - Zwei fesselnde Brettspiele’. Ravensburger (1975). (here)
☛ You can download my free Delta program here, but you must own the software Zillions of Games to be able to run it. (I recommend the download version.)
© Mats Winther, 2018 August