Draws by 50-move and threefold-repetition are optional but must be claimed with the arbiter; once a claim is made it is considered an offer and cannot be withdrawn, and the opponent can accept before the arbiter makes a ruling. | Draws by 50-move and threefold-repetition are optional but must be claimed with the arbiter; once a claim is made it is considered an offer and cannot be withdrawn, and the opponent can accept before the arbiter makes a ruling. |