Stibro is a loop-forming game played on a regular hexagonal board. The game is guar-
anteed to end with a winning loop. The recommended board size is 7 or larger. The pie rule may be used for balance.
Rules1. Players alternate placing one black resp. white stone on the board.
2. Passing is not allowed.
3. Each player must always have at least one free group of their colour on the board.
A free group is a group that both:
(a) does not touch the edge;
(b) has at least two cells between itself and at least one opponent group that does
not touch the edge.
Neither player may make a placement that would violate this restriction. Note that
this means neither player may place their first stone on the edge, and the second
player must start at least 2 spaces away from the first player.
4. The first player to complete a loop around empty cells and/or opponent pieces wins.
—description from the designer