The finesse obligatory is as follows:--You hold king, ten, seven, and three of a suit, and you lead { 200} the three; your partner plays the queen, and wins the trick, and returns a small card of the suit. From the fact of the queen winning, you know the ace is not held by your right-hand adversary; you also know your partner does not hold the knave. When your partner returns a small card of the suit, you know he does not hold the ace. If both the ace and knave are to your left, it matters not whether you play king or ten third in hand. If, however, the knave be to your right, your ten draws the ace, and you remain with the king, the best card of the suit. Hence you are obliged to play the ten third in hand in order to give yourself one chance--viz., that the knave is to your right; consequently, this is called the finesse obligatory.
Before a speculative finesse is attempted, the state of the score should be considered; if only one trick is required to win the game, and you hold ace, queen of a suit, the ace should be played, unless there is a certainty of this ace being trumped. Also a player should consider whether it is specially desirable that he obtain the lead, when he has the chance of a finesse. If the lead is important, the finesse should not be made; if the lead would be detrimental, it should generally be attempted.
What a finesse really is should now be comprehended. It is not merely playing the queen third in hand when holding ace, queen, but it is playing the queen on the chance that the king may be in the hand of the second player. If the second player hold none of the suit, no finesse can be made; the ace _must_ be played by the third player, if second hand has not trumped. It is curious how often bad players will commit the error of playing queen third { 201} hand, holding ace, queen, when the second player has failed to follow suit, and has refused to trump.
The fourth player has to win the trick if he can, with the lowest card in his hand. If he cannot win the trick, he plays his most worthless card.
From an examination of the leads, it will be seen that one main object is to convey information to your partner. The king is led before the ace, so that your partner may fairly conclude that, if the king wins the trick, you hold the ace. If, after the king, the queen be led, he obtains an additional piece of information. The science of Whist is in great measure based on this principle of giving information to your partner by means of the cards you play.