If he holds Ace and only one small card, the Ace should be played on the Jack led. If Third Hand has four trumps and a card of re-entry, the Ace should be played on Jack led, regardless of number, in older to lead trumps at once, to defend the suit.
When Partner Leads Low Cards, the Third Hand should do his best to secure the trick. If he has several cards of equal trick-taking value, such as A K Q, or K Q J, he should win the trick as cheaply as possible. The only finesse permitted to the Third Hand in his partner’s suit, is the play of the Queen, when he holds A Q and others; the odds being against Fourth Hand having the King.
Foster’s Eleven Rule. By deducting from eleven the number of pips on any low card led, the Third Hand may ascertain how far his partner’s suit is from being established. For instance: if the card led is the Seven, Second Hand playing the Eight, and Third Hand holding A J 6 3, from which he plays Ace, Fourth Hand playing the Five; the only card against the leader must be the King or Queen; he cannot have both, or he would have led one. If the Second Hand has not the missing card, he has no more of the suit. The number of inferences which may be made in this manner by observant players is astonishing. A great many examples and exercises in them are given in Foster’s Whist Manual.
Third Hand having None of the Suit, should trump anything but an Ace or a King on the first round. On the second round, if there is only one card against the leader, his partner should pass with four trumps, and allow the suit to be established. For instance: If the leads have been Ace, then Jack, Third Hand holding only one of the suit; he should pass if the Second Hand does not play King.
Third Hand on Strengthening Cards. Unless Third Hand has both Ace and King of the suit, he should pass any forced or strengthening lead which is not covered by the Second Hand. This obliges the Fourth Hand to open another suit, or to continue at a disadvantage.
Third Hand winning first round has the choice of four lines of play:
1st. To lead trumps, if he is strong enough.
2nd. To return the best card of his partner’s suit if he has it. This is imperative before opening any other suit but trumps.
3rd. To lead his own suit, if he can do anything with it. It is considered better play for the Third Hand to return the original leader’s suit than to open a long weak suit of his own such as one headed by a single honour.
4th. To return his partner’s suit even with a losing card, in preference to changing.