Always play third Hand High? (Rule of 3, Part 2)
                
                
                In Bridge, there is a axiom that goes, “play low in the second 
                seat – play high in the third seat.” After an opening lead, the 
                player in the second seat is in a prime position to become 
                finessed. By playing low in the second seat, the partner of the 
                leader (in the third seat) cannot be certain whether the player 
                in the second or fourth seat holds a crucial honor or 
                intermediate card; these cards may eventually be promoted to win 
                a critical trick. However, in third seat, either our partner 
                deliberately lead the suit or we called for the dummy card as 
                declarer. Either way, in third seat our predominant goal is to 
                promote a trick. So we generally play a high card in third seat.
                
                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. 
                In summary, third hand high is a useful axiom yet it does not 
                absolve the player from thoughtful play based on the big picture 
                - and that’s what makes our delightful game of Bridge so much 
                fun! Two good books covering third hand high (or not) are: “Defense” 
                (formerly known as the Heart Series) and “25 
                Bridge Myths Exposed.”