Defense -- 2nd Hand Play
In this instructional article on defense, our RHO will be leading to the trick (either declarer or dummy is leading to the trick). It won't matter if it is a suit contract or notrump.
The old saying for defense is: "Second Hand Low, Third Hand High." In general, when playing second to the trick, play low. The major exception is "cover an honor with an honor" (which also has exceptions). Don't you just love bridge?
In this brief summary, I think it will be helpful to start with a very common suit combination:
If the 6 is played from dummy, follow LOW with the four.
But, if the JACK is led from dummy, cover with the KING.
| |
| |
DUMMY |
| YOU |
 J76 |
A92
|
|
| |
DECLARER |
| |
Q or 3
|
If declarer leads low (3) from his hand, follow LOW with the two.
But, if the QUEEN is led from declarer, cover with the ACE.
Now let's look at all 4 hands:
If declarer leads this suit from dummy or hand, he should lose 3 tricks. When he leads low from dummy (or hand), the next defender plays low. If declarer leads an honor from either hand, the next defender covers.
This basic premise: "2nd hand low, but cover an honor with an honor" will cover most situations.
When declarer leads low from either hand, be wary about grabbing an ace when playing second to a trick. Usually, this is a losing play. Your ace will capture "air." Aces are meant to capture higher honors. Also, you often remove a guess; declarer leading up to king-jack (trying to decide who has the ace and who has the queen) will be delighted if you grab your ace, removing the guess. Here is a very typical ace-grab to avoid:
Declarer leads the 
2. If West grabs the ace, you can see what happens. West should play low, and declarer gets only one trick.
If they are in seven, then feel free to grab your ace. Every now and then, you will duck an ace and "go to bed with it." That's okay. If you never go to bed with an ace, you are grabbing them too quickly. I'd say that 90% of the time, it is wrong to take an ace when playing second to a trick.
As far as covering an honor with an honor, there are exceptions. Even experts don't always get it right. Here are two common exceptions, worth learning:
When you see the jack from declarer, don't cover. What good could it do? If covering won't promote anything in partner's hand, don't cover.
If dummy had 
AK9, then covering is okay (hoping to promote partner's 10).
The other main exception is: Don't cover the first honor. Cover the second honor. For example:
When dummy's queen is led, East should NOT cover. If he does, declarer will win the ace and finesse against West's 
10.
After the queen wins the trick and the jack is led next, East should cover.
Second-hand play is tough, but following the basic rules above should be good enough 90+% of the time.
You can find more of Larry's thoughts on defense in his DVD (https://www.larryco.com/bridge-store/detail/dvd-second-hand-play) or his webinars (https://www.larryco.com/bridge-store/detail/larry-teaches-defense-overview-part-1-of-2-webinar-aired-52820).
(updated July 21, 2020)
