The players sit around a table with the teammates (also called partners) sitting across the table facing each other. The four player positions are assigned the compass positions of North, East, South, and West. From your vantage point as a player you would usually consider yourself South, looking across at your partner in the North position.
The hand starts by dealing thirteen cards face down to each player. After looking at their cards, each player bids in turn clockwise around the table, starting with the dealer. A bid is a declaration of how many tricks (rounds of card play) the player thinks his team can win.
In the language of bridge, a bid is defined as the number of excess tricks over six. This is because there are 13 cards in each hand, and hence 13 rounds or tricks; therefore the bidding team is claiming that it can win at least half of the tricks (six) and then some. Hence, a bid of one means the team expects to win six tricks plus one, or seven total.
The range of bids therefore lies from one (6 + 1 = 7 tricks total) to seven (6 + 7 = 13, or all the tricks available). A contract at the 6 or 7 level is called a slam. A 6-level contract is a small slam, and a 7-level contract is a grand slam.
Each bid consists of the bid level plus a trump suit choice. The trump suit is the one intended to be supreme for that hand. That is, when a card of a trump suit is played, it beats all cards of all other suits, plus any other trump suit cards lower in rank (with Ace being high). However, there are specific restrictions on when you can actually play a trump card, which will described later. Also, a bid can specify “no trump”, indicating that no suit is chosen as trump.
Bridge also accords each suit a rank. Spades is the highest suit, followed by Hearts, Diamonds, and Clubs. In addition, No Trump, while technically not a suit, ranks above Spades for bidding purposes. Therefore, a bid of 1NT is higher than 1 Spades, which is higher than 1 Hearts, and so on.
The lower ranking Club and Diamond suits are known as the minor suits, while the higher ranking Heart and Spade suits are known as the major suits.
At the beginning of the hand, the dealer begins (or opens) the bidding. And as the bidding proceeds around the table, each player must either make a bid higher than the previous one, pass, or double the opponent’s bid.
A double is actually not a bid that’s twice as high, but rather a challenge to the opponents effectively stating “I dare you to make that contract”. A doubled bid can also be redoubled by the declaring team, meaning “Oh yeah, we sure can make that contract.” Doubling and redoubling can affect the score as described later.
During the bidding stage, the main problem facing the players is that they can only see their own cards. They cannot see the cards held by their partners, much less those of their opponents. So the bidding is largely a boasting game based on deductive reasoning and educated guesses (and to some extent, coded signals).
After one or more bids have been made and three players in a row pass on the opportunity to make a higher bid, the final bid becomes the contract which the bidding team has to fulfill during the card play stage. The bidding team is only awarded points if they win at least the number of tricks claimed in their bid. In fact, if they fail to win the number of tricks promised, the defending team is awarded penalty points.
So at this point, the game becomes a contest to see whether the declaring team can win sufficient tricks and make the contract, or whether the defending team can keep them from doing so, thereby setting (defeating) the contract.