The goal for good defense is:
- know as precisely as possible what the declarer has
- prevent them from implementing their strategy
The defenders' sources of information are:
- The bids (West opens 1♥ : they have at least 5, etc.)
- The declarer's way of playing (they play from dummy's short suit, they will try to ruff from the short hand)
- The information given by partner during card play, called signaling
For small cards: odd-even
The main information sent by partner is their number of cards in the suit being played. Or more precisely, whether they have an even or odd number of cards in the suit (then use the rest of the info to figure out if it's 2 or 4, 3 or 5, etc.).
We've already seen this for the opening lead:
- with an odd number of cards, play the smallest then go up (♣J9742: the 2, then the 4, etc.);
- with an even number of cards, play a high one (usually the 2nd highest) then the smallest (♠9752: the 7 then the 2).
You hold 864 in the suit led. The three cards are useless for winning a trick and you play odd-even. Which signal start do you choose?
Section quizYou have three Diamonds and dummy has four. Partner, who faithfully follows odd-even with useless cards, played a high one then a low one. They had at least two and at most three based on the cards already seen. How many Diamonds did the declarer have?
Section quizFor high cards: sequence head and lowest of equivalents
During play, when you lead a suit where you have 2 consecutive honors or more (a sequence), play the highest (the sequence head): your partner will understand that you have the next high card. Again, it's like the opening lead.
When you are in 3rd position however, look at this.
You are West, and during play you play the ♦3 and you see successively the ♦2, the ♦Q and the ♦A. Do you know where the Jack is? No.
Now change the trick a bit:
This time, it's the Jack that is taken by the Ace. And there, think for 5 minutes. Can the Queen be in South, like:
No. South is not crazy: they could take with the Queen and keep their Ace to make a 2nd trick, they won't deprive themselves.
So the Queen is not in South, and the position is rather:
You send more information to partner by playing the lowest of equivalent cards in 3rd position.
Your partner plays the 2, dummy plays the 5. In third position, you hold KQ93. Which card do you play?
Section quizIt's your turn to play and you will see... that we know a lot of things, actually.