If you hold the king of a suit once or twice guarded in one hand, and only small cards of that suit in the other, do not take a finesse, which may allow the adversary to lead through this king.
If you have a strong hand and a weak dummy you would, of course, prefer that the lead come up to you. Therefore, take your finesse, so that if it loses, you will have, at least, this advantage.
With ace, king, and jack in one suit, and especially if these cards are all in one hand, it is often good play to take one round of the suit before attempting a finesse. The fall of the cards may help you to locate the queen.
When you hold eight cards to the ace, king, and jack in the two hands, the adversary’s queen is frequently unguarded. Finessing then becomes a question of the score and of the possible loss that an unsuccessful finesse would entail. You should risk the loss of a trick in order to win the game, provided the loss of a trick does not lose the game. If the game cannot be won, and it is merely a question of winning or not winning the odd trick, do not finesse. That one trick may prevent the adversaries from winning the game on the next deal.
THE FINESSE OBLIGATORY
This is an arbitrary finesse, which is often forced upon you, when, unless the cards of a suit are in a certain position, there is no possibility of winning. Perhaps the best way of defining the finesse obligatory is to give an example showing the position as it most frequently occurs:
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“Z” is the dealer, and leads a low card to the king in dummy, which wins the first trick. The suit is returned, the ace being marked with “A.” If “A” holds both ace and knave, no matter how the dealer plays, “A” must win two tricks. Unless the knave is in “B’s” hand, and “A” holds the singleton ace, the adversary must win two tricks. The dealer should, therefore, play his lowest card, not the queen.
WATCHING THE DISCARDS IN ORDER TO LOCATE FINESSES
The amount of information to be gained from the adversary’s discards is apt to be underestimated. Careful notice of the discards, particularly in a “no-trump” hand, will often help you to locate honours and to determine where a finesse should be taken; moreover, it will simplify the end play, show you chances to throw the lead, and give you opportunities to force the opponents to lead up to your hand.