Defense

If you're Third Hand (partner has led the suit):

• Play "Third Hand High" rule to set up potential tricks for your side. Play the highest card necessary to force declarer or dummy to win with its high card.
• Always play the lowest of touching cards to give partner the most information about your strength. (Play the J from QJx; the 9 from J109.)
• If you're playing after dummy, be sure to bracket your honors if dummy plays low. (Play the J from KJx if dummy plays low from Qxx.)
  

If you're Second Hand (declarer or dummy is leading the suit):

• If an honor is led and you're next to play, follow the "Cover-an-Honor with-an-Honor" rule -- if declarer or dummy leads an honor (10 through Ace), play your higher honor on it if you have one. This forces declarer to use two of his honors to capture one of yours.
• With most other holdings, follow the "Second-Hand Low" rule -- if you're in doubt about which card to play, choose a low card. The main exceptions to this rule are:

1 - You have a sequence of honors (KQJx, QJ10xx, etc.) and want to be sure you force declarer to win a high card. In this case, play the lowest of your touching honors.

2 - You're covering an honor with an honor, or playing your ace to win a king or queen.

3 - You're reasonably sure your ace will be trumped later if you don't take it now.

If you're on lead after the first trick:

• If partner made the opening lead -- and if you're in doubt about what to do when you gain the lead later in the hand -- return partner's suit. This is an especially valuable guideline to follow when defending notrump contracts.
• If you want to switch suits, choose to lead through strength and up to weakness. Ideally, you want the opponent who holds the most strength in a suit to be the second hand to play to the trick. You want the hand with weakness in the suit to be fourth to play to the trick.
• Don't be afraid to lead a suit that you know declarer will trump -- you can sometimes weaken his trump holding by doing so.
• Don't be afraid to lead a trump. If it appears that your other possible leads will risk giving declarer a trick, a trump can sometimes serve as a safe exit.
• Don't lead a suit if both declarer and dummy are void. This is called a "ruff -and-sluff", and it often gives up trick by letting declarer trump in one hand and throw a loser from the other hand.
  

Count and Attitude Signals

To defend a bridge hand well, you need to be alert to -- and be able to process -- all the clues that are available. Some clues come from the bidding, which often gives you a general picture of who holds the length and strength in each suit. Your best source of information, though, is your partner, who can give you Attitude and Count Signals during the play. These signals are used by both defenders to exchange information about their length and honor holding in each suit. Here's how they work:

Attitude Signals

You can tell partner whether or not you "like" a suit by the size of the card you play when discarding the suit or when following suit to a trick you are not winning. A high card is a "come-on" signal -- it tells partner you have a possible trick in the suit (you have a high honor, or will be able to trump the third round of the suit) and that he should lead it again. A low card tells him you have no potential tricks in the suit (no honors, no shortness) and that he should consider leading a different suit.

Count Signals

When following suit or discarding, playing high, then low in the same suit tells partner you have an even number of cards in that suit. Playing low, then high shows an odd number of cards. If you're defending a suit contract, this signal tells partner whether or not you can trump the third round of a suit. In suit and notrump contracts, your count signal also helps partner determine how many cards declarer holds in the suit. This can be very valuable information if partner needs to know how long he should hold up winning an ace, for example.