Yet like most “rules”, there are several considerations before automatically playing a high card in third seat:

1. Play the “lowest of equals” over dummy cards – playing the higher of two touching honors misleads partner into thinking the Declarer holds the lower of a touching sequence.

2. When appropriate, keep a “cover card” (usually higher honor card) over the visible card in dummy – of course, the defender must carefully consider factors such as transportation, possible finesses, declarer’s short suits, etc.

3. Avoid winning a trick when gaining the lead at that moment would ultimately lead to losing additional tricks.

4. Consider keeping suit communications open in Notrump contract – playing low on the first round (ducking) to subsequently promote the suit when regaining the lead.

Let’s look at some illustrative examples – this discussion assumes fourth-best leads.

                4 3 2

A 10 9 8 7             K J 5

                Q 6

West leads the 10, the top of a sequence. East must go up with the King, otherwise declarer South will win the trick and switch to another suit.

               K 9 7

A 8 3 2               Q 10 4

               J 6 5

West leads the 2, the fourth best and promising a four card suit (otherwise West would lead a higher card, holding 5). After declarer plays the 7 from dummy, East must play Queen, otherwise South unnecessarily wins a cheap trick.

               8 7 6

K 10 4 3               Q 9 2

               A J 5

West leads the 3, the fourth best - as East, you can deduce this fact since you hold the 2; if West held 5+ cards, the lead would have been a card above the 3. In third seat, East must play the Queen, again third hand high in order to hold the declarer to one winner.

Now let’s look at a few hands involving dummy finesses.

                  Q 8

A 7 6 5 4 3            K 10 9

                 J 2

West leads the 5 to dummy’s 8. East must play the King – third hand high. Incidentally, did you use the Rule of 11 here? Here the formula is: 11 – 5 = 6
So after the lead of the 5, the remaining 3 hands have 5 cards above the 5. Sitting in the East seat, we can count 5 of the 6 so declarer South has only one card above the leader’s 5. Playing the King ensures the defenders get all their tricks. Now let’s modify the hand slightly.

                Q 8 2

A 7 6 5 4             K J 9

                10 3

After West’s lead of the 5 to dummy’s 8, East must play the Jack, not the King. This is an example of “low from equals” – since the dummy’s Queen is pinned, playing the Jack will win a trick just as effectively as the King and still keep the looming honor over the Queen later in the hand. It would be wasteful to play the King on the first trick and potentially give the opponents an undeserved trick later in the hand.

             Q 8 7

9 2                  A J 10 6 5

             K 4 3

During the auction East bids a long suit, so West leads the 9 – probably from a doubleton. East may play a low card since the only outstanding honor above the leader's 9 is the Ace. Here’s an exception to playing third hand high. East should keep a “cover card” – the Ace honor over dummy’s Queen. In addition to keeping the important cover card, West can deduce that East has the Jack and 10. Now let’s investigate third hand play when leader has a strong honor sequence.

                J 3 2

K Q 10 5 4             A 6

                9 8 7

West leads the King, the top of a broken sequence (recall we should lead the top of the touching honors). In third seat, East should play the Ace and return the suit. If East played the 6, West will certainly play again; this would force East to play the Ace, blocking the suit – a most unfortunate situation. Next, let’s examine a situation where third hand uses a ducking strategy to belatedly promote a suit (opponents are playing a Notrump contract).

             3 2

10 4                 A K Q 6 5

            J 9 8 7

Imagine East bid this suit, South overcalled Notrump and the opponents eventually ended up in 3 Notrump. After West dutifully leads the 10, should East win the trick and continue playing the suit? The answer is, “it depends!” If East has an outside entry, then going up with the top honor will work – East loses the fourth trick to South’s Jack but later wins a trick in an outside suit and cashes the fourth trick in this suit to set the contract. But what about the situation where West has the only winner in an outside suit? If East were to win the Ace-King-Queen and East later gets in the lead, West would not be able to return a card to East’s promoted suit. We call this keeping the suit communication open. In essence, when the long hand does not have an outside entry, be careful to disrupt the vital suit communication channel. Finally, let’s explore a ducking maneuver where the opponents are in a suit contract and partner is hoping to gain a ruff.

           J 8 6

9 2              A 10 7 5 4

          K Q 3

West leads the 9; should East play third hand high with the Ace? Again, the answer depends on who has an outside suit entry. If East has an outside Ace of trump, it would be okay to win the Ace here and return a low card in the suit – when the declarer wins the trick and plays a trump, East wins and plays a third card in this suit to give West a ruff. However, if West potentially held the Ace of trump or King-third “behind” the declarer, than clearly East should not win the first trick. As we saw before, when West regains the lead and returns the remaining singleton in the opening suit, East wins the Ace and gives West a well-deserved trump ruff.