Source: Mr Bridge
Generally, the correct method of playing a suit is to play the high cards from the shorter holding first so that the suit runs smoothly:
 K Q 4 |
| A J 3 2 |
You start with the king and queen from North’s shorter holding (three cards) and then play the four to South’s ace and jack – four easy tricks. If you play the ace or jack first, you block the suit. A blockage means that to run the suit
you need a side entry. If you began with the ace, you could take the king and queen, but then would have to use
another suit to get over to the jack.
Sometimes a suit starts blocked or a finesse or similar play blocks the suit:
 K Q |
 A 7 6 |
|
| A 7 6 5 4 |
Q J 10 9 8 |
You cannot run the diamonds without crossing to hand in another suit. You could play the hearts for one loser: take the ace and knock out the king. To avoid a loser, you want to finesse. You lead the queen and run it: it wins the trick; you lead the jack, which also wins, but now the suit is blocked with the bare ace left in hand. After all follow twice, the other hearts are good as West’s king will fall under your ace, but you need a side entry to the South hand to run the rest of the suit.
Another common blockage arises here:
| A 7 6 3 2 |
| Q 4 |
You can make your queen and ace if East holds the king. You lead small from dummy towards the queen. If East has
the king, he may well play it; this sets up your queen but blocks the suit with the queen left facing A-7-6-3. You must be wary if a long suit starts blocked or may become so – your plan must cater for the necessary entries.
A 4 3 A K 4 A 8 7 6 A 4 3 |
||
| Q 10 7 6 5 9 8 2 Q 9 K 7 6 |
J 8 Q J 10 5 3 K J 5 4 5 2 |
|
| K 9 2 7 610 3 2 Q J 10 9 8 |
South is in 3NT and West leads a low spade. You have six top tricks with extra tricks available in clubs and possibly
diamonds. A finesse might bring in the whole club suit, but when the long suit is in the weak hand you need to be careful. If you use up South’s spade entry to take two successful club finesses, the suit will be blocked and you will make only three club tricks. Instead, you should win the initial spade lead with dununy’s ace and knock out the king of clubs. Your king of spades will be the entry to reach your long clubs.
| Q 6 A K 8 A 4 3 2 9 8 7 2 |
| A 8 6 5 4 J 8 7 A K 5 4 3 |
South is in 3NT and West leads the spade jack. When you cover the jack with the queen, East covers with his king
and the suit is going to be wide open. You duck once, but have to take the second round. You now need to run nine
tricks without losing the lead, which means clubs must split 2-2. However, if you mistakenly play the ace-king
without considering dununy’s holding, you will come unstuck. While the luck is with you (clubs are 2-2), you can make only four club tricks, as there is no way to reach your fifth club. You would have to settle for eight tricks in this case. Of course, the way to solve the problem is to keep the club two in dummy. You play the seven and eight underneath the aceking.
Then, with the clubs falling, you can win the third round with the nine of clubs and finally cross to your two remaining clubs by leacling the two to the five.
Conclusion
When you consider the play of a suit, you should check for any blockages – those there already and those that your
play will create. As always, try to do this at trick one as, very often, a crucial entry will go on the very first trick.