Rive

Rive can be played on any odd-sized, hexagonally patterned board, which starts out empty. The two players, Black and White, take turns placing stones of their own color on unoccupied cells on the board. There will always be a placement available. Players cannot pass on their turn. The game ends when the board is full. The goal is to claim the majority of cells. Draws cannot occur in Rive. Stone placementA group here is comprised of interconnected stones of both colors. If you can place a stone in isolation, you must do so. Otherwise your stone must be placed adjacent to up to three groups, of which the largest must be as small as possible. Capturing placementsWhen you place a stone that connects to two or three groups, you must remove stones from the newly formed group, of either or both colors, to bring the group size down to one stone larger than the largest of the groups that was so combined. Selecting stones for removal from the newly formed group must be done in a way that does not split the group into two or more smaller groups. There is no requirement to make a capturing placement if a non-capturing placement is available. When you make a capture, you must add another stone to the board while it's still your turn. And you must continue to add stones during your turn until you make a non-capturing placement.