Bidding box for home-played games. Use of bidding boxes has several advantages over oral bidding: it reduces noise in the room, prevents bidding being overheard at neighboring tables, allows easier review of the auction, and reduces the opportunity to pass unauthorized information to one's partner (intentionally or not) by the manner and intonation in which one makes one's bid. A bidding box is typically a plastic box with two slots, each containing a set of bidding cards. One slot contains 35 cards with symbols of bids (5 denominations—clubs (), diamonds (), hearts (), spades (), and notrump (NT)—in seven levels of bidding,
Contract bridge has been played, all four players slot their cards back into the board, ready to be played by the next table. The dealer opens the auction and can make the first call, and the auction proceeds clockwise. When it is their turn to call, a player may pass—but can enter into the bidding later—or bid a contract, specifying the level of their contract and either the trump suit or no trump (the denomination), provided that it is higher than the last bid by any player, including their partner. All bids promise to take a number of tricks in excess of