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,
Jump bidding strategy is to jump if-and-only-if the signal is at least 36. So if Xenia's value is e.g. 33 and Yakov's value is 39, then Xenia will pass and Yakov will jump, so Yakov will win and pay only 24. In contrast, in a simple Japanese auction, Xenia will stay up to her value of 33, so Yakov will win and pay 33. This outcome seems counter-intuitive from two reasons: Jump-bidding is a very crude form of communication: it does not communicate my actual value, it only signals that my value is above a certain threshold. The careful selection of the