69. A card dropped on the floor or elsewhere below the table, or so held that it is seen by an adversary but not by the partner, is not an exposed card.
70. Two or more cards played simultaneously by either of the declarer’s adversaries give the declarer the right to call any one of such cards to the current trick and to treat the other card or cards as exposed.
70a. Should an adversary of the declarer expose his last card before his partner play to the twelfth trick, the two cards in his partner’s hand become exposed, must be laid face upward on the table, and are subject to call.
71. If, without waiting for his partner to play, either of the declarer’s adversaries play or lead a winning card, as against the declarer and dummy and continue (without waiting for his partner to play) to lead several such cards, the declarer may demand that the partner of the player in fault win, if he can, the first or any other of these tricks. The other cards thus improperly played are exposed.
72. If either or both of the declarer’s adversaries throw his or their cards face upward on the table, such cards are exposed and liable to be called; but if either adversary retain his hand, he cannot be forced to abandon it. Cards exposed by the declarer are not liable to be called. If the declarer say, “I have the rest,” or any words indicating the remaining tricks or any number thereof are his, he may be required to place his cards face upward on the table. He is not then allowed to call any cards his adversaries may have exposed, nor to take any finesse not previously proved a winner unless he announce it when making his claim.
73. If a player who has rendered himself liable to have the highest or lowest of a suit called (Laws 80, 86, and 92) fail to play as directed, or if, when called on to lead one suit, he lead another, having in his hand one or more cards of the suit demanded (Laws 66, 76, and 93), or if, when called upon to win or lose a trick, he fail to do so when he can (Laws 71, 80, and 92), or if, when called upon not to play a suit, he fail to play as directed (Laws 65 and 66), he is liable to the penalty for revoke (Law 84) unless such play be corrected before the trick be turned and quitted.
74. A player cannot be compelled to play a card which would oblige him to revoke.
75. The call of an exposed card may be repeated until it be played.
LEADS OUT OF TURN.
76. If either adversary of the declarer’s lead out of turn, the declarer may either treat the card so led as exposed or may call a suit as soon as it is the turn of either adversary to lead. Should they lead simultaneously, the lead from the proper hand stands, and the other card is exposed.