On a hexagon of cells, four-in-a-row wins, yet a careless three-in-a-row loses on the spot, so every stone is a tightrope.
Players alternate dropping stones onto empty hex cells. Lines are counted along the three directions of the hex grid, and the length of your runs decides the game in an instant.
The rules are Yavalath's: on a hex board, make a line of four to win, but make a line of three first and you lose. It is a notable game because no person designed it — the rule set was produced in 2007 by LUDI, a program that evolves new games from existing ones, and it went on to rank among the top hundred abstract games on BoardGameGeek.
That lose-on-three condition is the entire idea, and it inverts the instinct every line game trains.
Three in a row is normally progress toward four. Here it is a loss, so you must reach four without passing through three — which means jumping a gap and filling it, and means an opponent can win by forcing you to complete a three you never wanted.
Tritavo reimagines the classic make-a-line connection game with a hexagonal board and a do-not-make-three twist that flips the usual instinct. It is an original free browser game with AI, local and online play.