Playing the cards
Defensive signals
Defenders may not speak, and each sees only 26 cards. Everything they tell each other has to travel in the spot cards they were going to play anyway, which is why bridge has three signals rather than one, and why knowing which is being given matters more than knowing any of them.
Attitude: the first one to learn
When partner leads a suit and you cannot beat what is played, your card says whether you want the suit continued.
A high spot card encourages. A low one discourages. Holding ♥ 8 3, play the 8 if you like hearts and the 3 if you do not.
"High" and "low" are relative to the cards you hold, not absolute. The 6 from ♥ 6 2 is encouraging; the 6 from ♥ Q 9 6 is not.
Count: when declarer is running a suit
When declarer leads a suit, you rarely have an opinion worth giving, so your cards show how many you hold instead.
High-low means an even number, low-then-high means odd. With ♦ 8 4 you play the 8 then the 4; with ♦ 8 6 2 you play the 2 first.
Partner uses it to work out declarer's length, which is what tells them when to take an ace. Hold up until the round declarer runs out and their long suit is dead.
Suit preference: the third question
Sometimes attitude is pointless and count is obvious — most clearly when you are giving partner a ruff. They are going to trump it either way; what they need to know is what to lead back.
The card you give them says which of the two other suits you want. A high card asks for the higher-ranking, a low card for the lower.
Hearts are trumps, you give partner a club ruff, and they must return a spade or a diamond. Your highest club asks for the spade; your lowest asks for the diamond.
Which signal is this? — the part usually left out
Knowing all three is useless if partner cannot tell which one you just gave. The order of priority is nearly always:
- Partner led and you have an opinion — attitude. This covers most of the signals in a normal deal.
- Declarer led — count. You have no opinion worth giving about a suit declarer chose.
- Attitude and count are both pointless — suit preference. A ruff, a trump suit being drawn, or an obviously singleton dummy.
Discards follow the same logic: the first discard is usually attitude about the suit you are throwing.
Upside-down signals
Many partnerships reverse attitude and count: low encourages, and low-high shows an even number.
The argument is that encouraging with a low card keeps your high spot cards, which can be worth a trick. The cost is that everybody learns standard first, so a mixed partnership will misread each other on the very first defence.
Neither is measurably better. What matters is that both of you know which you are playing, and that the opponents are told when they ask — your carding agreements are theirs to know too.
The three that cost most
- Signalling with a card you need. The signal is not worth a trick. Throw the useless card and let partner work it out.
- Encouraging on air. A high card because the suit looks nice, with no honour behind it, costs partner the trick they spend continuing.
- Signalling when declarer is watching. They are, always, and they can read your carding as well as partner can. On a hand where partner cannot use the information, do not give it.