Fergus writes: 'It is possible to use repeated checks to force the same position to repeat three times.'
See this page for a moving diagram of perpetual check. It is worth noting that sometimes the 50 moves rule will apply before the 3-times repetition rule. As I wrote back on [2004-08-27], in my database is the game [R. Pert - M. Franklin, 1996] in which both players have two rooks on the board. Black sets up a possible stalemate position on move 33 by advancing his passed Pawn to h3. All White needs to do is sacrifice both Rooks. After 21 consecutive Rook checks, they agreed to a draw. Of course, Black can always end the checks (and stalemate White) by capturing the last Rook.
Fergus writes: 'It is possible to use repeated checks to force the same position to repeat three times.'
See this page for a moving diagram of perpetual check. It is worth noting that sometimes the 50 moves rule will apply before the 3-times repetition rule. As I wrote back on [2004-08-27], in my database is the game [R. Pert - M. Franklin, 1996] in which both players have two rooks on the board. Black sets up a possible stalemate position on move 33 by advancing his passed Pawn to h3. All White needs to do is sacrifice both Rooks. After 21 consecutive Rook checks, they agreed to a draw. Of course, Black can always end the checks (and stalemate White) by capturing the last Rook.