Contract, declarer, dummy and defenders
When the auction ends, every player receives a clear role for the card-play stage.
The final contract
The last bid followed by three passes is the contract. It specifies the target number of tricks and the trump suit, or No Trump. The partnership that made the final bid becomes the declaring side; the other partnership defends.
Contract: 4♠. North–South must win at least ten tricks with spades as trump.
Who becomes declarer?
Declarer is the first player in the winning partnership who bid the denomination of the final contract. It is not necessarily the person who made the final bid.
In the example, South first bid spades, so South is declarer. North's later spade raise supported the suit but did not make North declarer.
Declarer
Tries to make the contract and chooses the cards played from both the declarer's own hand and dummy.
Dummy
Declarer's partner. After the opening lead, dummy places all 13 cards face up in suits for everyone to see.
Opening leader
The defender immediately to declarer's left leads the first card. This happens before dummy's cards are exposed.
Defenders
Work together to take enough tricks to defeat the contract. Each defender plays only their own cards.
How dummy is played
Dummy does not decide which card to play. Declarer names or selects a card from dummy whenever it is dummy's turn. The physical player sitting as dummy may place that card on the table, but acts only on declarer's instruction.
Dummy's exposed cards are legal information for everyone. Declarer plans using two visible hands. Each defender sees dummy plus their own hand, but not partner's or declarer's hidden cards.
Making or defeating the contract
If declarer wins at least the promised number of tricks, the contract is made. Extra tricks are overtricks. If declarer falls short, the missing tricks are undertricks and the defenders receive the score.
Quick role check: declarer's left-hand opponent leads; declarer's partner becomes dummy; declarer plays both declaring hands; the other two players defend.