One game of Contract bridge followed from the deal to the finish, move by move, with the reason for each choice.
You and Bo are partners against Ada and Cleo. You deal, so you speak first. Your hand: ♠ A K 4, ♥ A Q J 8 5, ♦ K Q 3, ♣ 9 2. Counting 4 for an ace, 3 for a king, 2 for a queen and 1 for a jack, that is 19 points with five hearts.
Bo, opposite you, holds ♠ 8 6 2, ♥ K 9 6 3, ♦ A 8 5, ♣ Q 7 4: 9 points and four hearts. Neither side is vulnerable yet.
You open 1♥, promising at least twelve points and five hearts. Ada passes. Bo raises to 2♥, which shows support for hearts and a modest hand. Cleo passes.
Your 19 points and Bo's six to nine add up to about 25–28, enough for game, and hearts is a major suit where game is ten tricks. You bid 4♥. Ada, Bo and Cleo pass, and three passes end the auction. The contract is 4♥, and because you named hearts first, you are the declarer.
The player on the declarer's left makes the opening lead, so Ada leads K♣ from a clubs holding headed by the ace and king. Bo then lays his whole hand face up as the dummy, and from now on you play both hands.
Before playing to the first trick, count. You can lose two clubs straight away. You have a spade loser too, because you have three spades and only the ace and king. Everything else — five hearts and three diamonds — should be winners.
Ada's K♣ wins the first trick: dummy 4♣, Cleo 3♣, you 2♣. Ada continues with A♣, and that wins too: dummy 7♣, Cleo 6♣, you 9♣. The defence has its two tricks.
Ada tries a third club, J♣. From the dummy you play Q♣, which is now the highest club left, and Cleo follows with 8♣. You have no clubs left, and instead of trumping a trick your partner is already winning, you throw away your losing 4♠. The spade loser has disappeared.
The dummy won the trick, so you lead from there: 3♥ to your J♥, with Cleo playing 2♥ and Ada 4♥. Then A♥ from your hand collects Ada's 10♥ and Cleo's 7♥. That is all four of the opponents' trumps gone in two rounds.
Now nothing can be trumped, and your remaining cards are all winners: A♠ and K♠, three more hearts, and K♦, Q♦ and the dummy's A♦. You take every remaining trick, eleven in all.
You bid ten tricks and took eleven. The four tricks you bid in hearts are worth 30 each: 120 points below the line, which is more than 100 and so wins a game for your side. The overtrick is worth 30 above the line, where it counts for the final total but not towards a game.
Your side is now vulnerable: one more game wins the rubber, but going down will cost more. The next deal passes to Ada.