Three in a row takes a piece
Nine Men's Morris online
Play Nine Men's Morris online with a friend or a bot. Place nine pieces, close lines of three, and take one of your opponent's pieces each time — until only two are left.
Central Europe has played this for centuries and the same thing still decides it: not whoever builds mills, but whoever builds a double mill — two lines sharing a piece that can be opened and closed every single turn. Whoever gets one takes a piece a move.