involves a single item for sale and each participant has as an independent private value for the item auctioned, the expected payment and expected revenues of an English auction is theoretically equivalent to that of the Vickrey auction, and both mechanisms have weakly dominant strategies. Both the Vickrey and English auction, although very different procedurally, award the item to the bidder with the highest value at a price equal to the value of the second highest bidder. Variations There are many variations on this auction system. Sometimes, the reserve price is not revealed. Also, bids may be made with signals instead of being called out. Such signals can include tugging an ear or raising a bidding paddle. Another variation on the English auction is the open-exit auction, where the bidders must announce that they are dropping out of the bidding and they cannot re-enter. In France, when the last bid has been made in an auction for an art object, a representative of the state can say "Préemption de l'état" ("Pre-emption of the state") and buy the object for the highest bid. Some housing cooperatives similarly allow members of the cooperative to pre-empt any buyer of a house constructed by the cooperative. Scottish auction In a Scottish auction (or also time-interval auction), all bidding should be completed within a certain time interval. This ruling provides the bidders an appropriate amount of time for consideration. Speed is not important in this type of auction. Candle auction A candle auction is a variation in which the end of the auction is signaled by the expiration of a candle flame. This was intended to ensure that no one could know exactly when the auction would end and make a last-second bid. Japanese auction A Japanese auction is a variant in which the current price changes continuously according to the auctioneer's clock, rather than by bidders' outcries. Bidders can only decide if and when to exit the arena. At first glance, this seems equivalent to English auction: apparently, in an English auction, it is a dominant strategy for each buyer whose price is above the displayed price, to always bid the minimal allowed increment (e.g. one cent) above the displayed price, so the price should increase continuously. However, in real-life English auctions, jump bidding is often observed: buyers increase the displayed price much more than the minimal allowed increment. Obviously, jump-bidding is not possible