Morro is played on an 8x8 square grid using two pieces per player and 19 neutral pieces. To start the game one player places all four players' pieces on the edge of the board and any number of neutral pieces on non-edge spaces. The other player may then either move first and choose which color to play, or may take the remaining neutral pieces (counting towards the victory condition) and let the other player choose a color and move first.
A turn consists of moving either of your pieces in any straight line over empty spaces. After a move, if the moving piece and any other piece (including one of the opposing pieces) enclose an unbroken line of neutral pieces (or opposing pieces), the enclosed pieces are captured.
The object of the game is to capture a majority of the 19 neutral pieces.
As a variant, one piece of each player moves as described above, and the other can jump over pieces (jumped pieces are not captured).