If the Jack is led from K Q J x x, and wins the trick, partner may be credited with the Ace; and if the original leader has four trumps, and a card of re-entry, he should quit his established suit, and lead trumps to defend it.
If the King and Ace have been led from A K x x, partner dropping the Queen on the second round, the suit should be changed, unless the original leader is strong enough to risk weakening his partner by forcing him to trump the third round. Four trumps are generally considered to be sufficiently strong to justify a force in this position. Some players will force, even with a weak hand, if the two cards played by the partner are small, and he has not availed himself of an artifice known as calling for trumps, which we shall consider presently.
If the King and Ten have been led from K Q J 10, and on the second round one adversary has dropped the Eight, the other the Nine; the suit should be changed, as partner must have the Ace, and neither of the adversaries have any more. To lead such a suit again is called forcing both adversaries; as it allows one to make a small trump and the other to get rid of a losing card.
If the Four has been led from J 8 6 4, and the adversaries have won the first trick with the Nine or Ten, A K Q must be against the leader and his partner, and the suit should be abandoned as hopeless, unless it is feasible to force the partner.
If at any time there is a strong indication that the adversaries will have a cross-ruff, it is usually best to stop leading plain suits, and attempt to get out the trumps.
THE LEADER’S PARTNER, or the Third Hand, has several conventional plays to remember; the most important of which are the following:
When Partner Leads High Cards, the Third Hand has usually little to do but to play his lowest of the suit. The exceptions are:
If he holds A J alone, on a King led, the Ace should be played.
If he holds A Q alone on a Ten led, the Ace should be played. With A Q x, the Ten should be passed. With Ace and small cards, the Ace should be played on the Ten. With Queen and small cards the Ten should be passed. When Third Hand plays Queen on a Ten led, it should be a certainty that he has no more of the suit.
If he holds A K and only one small card, the King should be played on a Queen led.