INTRODUCTION Halfcut is a two-player game played on a square board of any size, initially empty. The two players, Red and Blue, take turns placing their own checkers onto unoccupied squares, one checker per turn, starting with Red. Passing is not allowed, but if you don't have an available placement, your turn is skipped. Mark Steere designed Halfcut in August 2023.
OBJECT Red must form a path of red checkers (interconnected via horizontal or vertical adjacencies, or both) connecting the two red sides of the board. Blue must form a path of blue checkers connecting the two blue sides of the board.
GROUP A group here is a monocolored group of checkers interconnected horizontally or vertically, or both. Diagonal adjacencies are irrelevant in Halfcut.
CROSSCUT A crosscut is comprised of four adjacent checkers arranged in a square. Two of the checkers are red and two are blue. Like-colored checkers are diagonally opposed in the square.
CROSSCUT GROUP A crosscut group is the group that contains a crosscut checker.
CROSSCUT RULE You can only form a crosscut if by doing so you create a new crosscut group which is larger than at least one of the enemy crosscut groups of the crosscut.
CHECKER REMOVAL Having formed a crosscut, immediately remove the enemy crosscut checkers which are part of enemy crosscut groups which are smaller than your newly formed crosscut group, concluding your turn.
SIMULTANEOUS CROSSCUTS In order to make a placement which would form two crosscuts simultaneously, you would have to satisfy the crosscut rule for both of the crosscuts, each considered separately.