Crossway Rules

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INTRODUCTION
Crossway is a played with a Go set. The board starts out empty. Each player takes possession of all of the stones of one color. Draws and ties cannot occur in Crossway.

STONE PLACEMENT
Players take turns adding their stones to the board, one stone per turn. A player must never complete a checkerboard formation as shown in Figure 1. Figure 2 shows all available placements for Black (V), marked with '?'s. Black makes the first placement of the game. Each player will always have a placement available and must make a placement on his turn. Crossway makes use of the pie rule. See the PIE RULE section below.

                . . . .         . . . .
                . H V .         . V H .
                . V H .         . H V .
                . . . .         . . . .
      Figure 1 -- forbidden patterns (checkerboards)

                ? H V V V
                H . H ? H
                V V V . H
                V H ? H V
                H . V . H
      Figure 2 -- legal placements for Black (H)
              (marked with ?)

OBJECT OF THE GAME
For White (H) to win, White must form a contiguous sequence of white stones connecting the West edge to the East edge of the board. Each stone in the sequence must be connected to neighboring stones in the sequence via horizontal, vertical, or diagonal adjacencies. Likewise for Black (V) and the North and South edges. A corner is considered to be part of both adjoining edges. In Figure 3, White has won the game.

           . . . . H    
           V . . H V   
           V H H V .    
           H . V . .    
           . . . . .    
      Figure 3 -- White (H) has won

PIE RULE
As noted earlier, Black (V) makes the first placement. On White's first turn, White has the option of swapping sides (becoming the black player). Or White can simply add a white stone to an unoccupied point. In either case, after White's placement players take turns adding their own stones to the board, one stone per turn, starting with Black.