Serious 3NT Serious 3NT Serious 3NT is a contract bridge bidding convention. It is used in game-forcing auctions where a major suit has been agreed upon. 1–2 if using 2/1 Game Forcing or 2–3 (Agreeing spades) The next bid indicates suitability for slam: Since Spades are the agreed trump suit, Three No Trump is not usually the best contract. Using Serious Three No Trump, a bid of Three No Trump says "I am Serious about slam", i.e. "I have a good hand". Bypassing bidding Three No Trump says "I am not Serious about Slam". Examples shown in the above auction. If one
Revenue equivalence with the highest bid simply pays its bid, if all players bid using a bidding function formula_28, this is a Nash equilibrium. In other words, if each player bids such that they bid the expected value of second highest bid, assuming that theirs was the highest, then no player has any incentive to deviate. If this were true, then it is easy to see that the expected revenue from this auction is also formula_26 if formula_3 wins the auction. To prove this, suppose that a player 1 bids formula_31, effectively bluffing that its value is formula_32 rather than formula_9. We