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,
Japanese auction Japanese auction A Japanese auction (also called ascending clock auction) is a dynamic auction format. It proceeds in the following way. Suppose a buyer believes that the value of the item is "v". Then this buyer has a simple dominant strategy: stay in the arena as long as the displayed price is below "v"; exit the arena whenever the displayed price equals "v". This means that the Japanese auction is a truthful mechanism: it is always best to act according to your true value, regardless of the others' values. When all buyers play their dominant strategies, the outcome is: A