twiceFour – Two-player board game

Two lines of four win the round – you only slide, and every line counts once.

twiceFour is a two-player board game online, one of the games for two on MindDuel: no download, against the computer or against others, as a guest with no sign-up. A strategy game without dice and a variation on “4 in a row”: nothing is dropped in – both sides start with five pieces each in the same setup, rotated by 180°, and move only horizontally or vertically.

Example: Cross already has one point from the line d2–d5 and occupies b1, c2, d3, d4 and d5; d2 and e4 are empty. Which move wins the round? Solution: d4 to e4 completes the diagonal b1–e4: second point, round won. c2 to d2 completes d2–d5 again but earns no point.

Levels: Seven levels: 60, 50, 40, 30, 25, 20 and 15 seconds per move. The computer looks one half-move ahead on level 1 and up to eight on level 7.

You practice thinking several moves ahead: setting up your own lines, blocking your opponent’s in time, managing your time per move.

How to play

Before round 1, each player picks a piece, cross or circle. If both want the same one, it’s decided by lot.
or
Nothing is placed: both start with five pieces each on the board. Eleven of the 21 points are free, the center among them.
Players take turns moving one step: one of your pieces moves to a free neighboring point, horizontally or vertically. There are no diagonal moves, and if you can’t step, you skip your turn.
Four of your pieces on one of the 16 lines score a point – four of those lines are diagonal. The pieces stay put, but the same line never scores again this round.
The first to two points wins the round – a move that completes two lines at once scores both. You also lose the round if your time runs out or you resign.
2 lines
The round ends after 80 half-moves. Then whoever has more points wins; on a tie, the better build-up counts. It’s a draw only if that is equal too.
The round also ends when the same position comes up for the third time – all pieces on the same points, the same player to move. The second time, “2nd repetition” warns you.
Better build-up means: for every line where your opponent has no piece and that hasn’t scored yet, your pieces in it count squared – one is 1, two are 4, three are 9. The higher total wins.
Two rounds: the lot decides who starts round 1, the other player starts round 2. A win counts 1 point, a draw ½ – and if it’s 1–1 after that, a third round decides; again the lot picks who starts it.
Win 1Draw ½

Level 1 gives 60 s per move, level 4 still 30 s – level 7 only 15 s.