Serious Three No Trump

A Contract Bridge

Contract bridge

Contract bridge, usually known simply as bridge, is a trick-taking card game using a standard deck of 52 playing cards played by four players in two competing partnerships with partners sitting opposite each other around a small table...

 bidding convention. Used in a Game Forcing auction where a
Major suit

Major suit

In the card game contract bridge, the major suits are spades and hearts . The major suits are of prime importance for tactics and scoring as they outrank the minor suits while bidding and also outscore them...

 is agreed.

1–2 if using 2/1 Game Forcing

2/1 game forcing

2/1 game forcing is a bidding system in modern contract bridge in which, after a one-level opening bid, a non-jump response in a new suit at the two level commits the partnership to bidding at least game....

2–3 (Agreeing spades)

The next bid indicates suitability for slam:

• 3NT: strong (Serious 3NT)
• 4/4/4: Cuebid, but not strong (non-serious).
• 4♠: Truly minimum.

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 player bypasses 3NT with a Cuebid (and is 'not serious'), then a Cuebid by partner indicates that he is serious. Note that in the example auction above, if the strong hand is next (after the 3 bid, he can differentiate between a strong hand, a weak hand that has a control (in case partner is strong) or a minimum hand.

Serious Three No Trump was devised by and named by Eric Rodwell

Eric Rodwell

Eric Victor Rodwell is an American professional bridge player. He has won the Bermuda Bowl representing the U.S. five times and is one of ten players who have won the so-called triple crown of bridge: the Bermuda Bowl, the World Open Pairs and the World Team Olympiad...

. Citations: Various
articles in the American Contract Bridge League

American Contract Bridge League

The American Contract Bridge League is the largest contract bridge organization in North America. It promotes the game of bridge in the United States, Mexico, Bermuda, and Canada, and is a member of the World Bridge Federation...

 Bulletin (magazine). Convention
cards submitted to the World Bridge Federation

World Bridge Federation

The World Bridge Federation is the world governing body of contract bridge. The WBF is responsible for world championship competition, most of which is conducted at a few multi-event meets on a four-year cycle...

.

Frivolous 3NT

Some partnerships reverse the meaning of 3NT in this situation. A weak hand bids 3NT to indicate no additional strength. This has the effect that a weak hand will not pinpoint a control for the defense.