The Attackers have the first move, then turns alternate between players.
Pieces can move horizontally or vertically (never diagonally). They can also move any number of squares unless stopped by the presence of another piece, a refuge square, or the edge of the board.
Pieces are captured by flanking (i.e., sandwiching an opponent's piece between two of your pieces OR sandwiching an opponent's piece between one of your pieces and an empty refuge). Whenever a piece is captured, it is removed from the board.
It is possible to move a piece so that it causes more than one piece to be flanked. In one move, the maximum number of pieces that can be captured is 3.
Capture must always be a deliberate act, so a piece can choose to move between two opposing pieces into a sandwiched position and not be captured.
A row of pieces at the edge of the board may also be captured by completely surrounding them against the board edge, so that none of them have room to move. This capturing move must be a flanking move to a square at the edge of the board. It's called a shield wall capture.
To capture the king, you must flank him on all sides with Attackers, or on three sides with the Attackers, if the fourth side is the center square or one of the board edges, so he cannot move.
Only the king can move onto a refuge. A refuge is considered a hostile square to all other pieces.
Once the king has left the center square, he cannot return to it. This is now a hostile square (like the refuges). In spite of this fact, the king and all other pieces can pass over it while moving around the board.
The goal of White is to get their king to a refuge (i.e., one of the four corner squares). The goal of Black is to capture the king or surround all of the king's forces so that none can reach the board edges.