Editing 2/1 game forcing

{{Short description|Contract bridge bidding system employing 2/1 as game forcing}}
'''2/1 game forcing''' (''Two-over-one game forcing'') is a [[bidding system]] in modern [[contract bridge]] structured around the following responses to a one-level opening bid:
#a non-jump response in a new suit at the one-level is constructive and forcing for one round,
#a non-jump response in a new suit at the two-level is forcing to [[contract bridge glossary#G|game]], and
#a 1NT response to a major opening is forcing for one round and indicates insufficient values to immediately commit to game or bid a suit at the one-level.

The 2/1 game force does not apply to responses by a passed hand, or if there is an intervening {{gcb|call}} by an opponent. Other responses are per [[Standard American]] methods in accordance with {{gcb|partnershipunderstanding|partnership agreement}}.

==Game forcing auctions==
The 2/1 auctions are: 1{{Diams}}&ndash;2{{Clubs}}, 1{{Hearts}}&ndash;2{{Clubs}}, 1{{Hearts}}&ndash;2{{Diams}}, 1{{Spades}}&ndash;2{{Clubs}}, 1{{Spades}}&ndash;2{{Diams}}, and 1{{Spades}}&ndash;2{{Hearts}}.

===Variations===
The following variations may be made by {{gcb|partnershipunderstanding|partnership agreement}}:
*Some play that 1{{Diams}}&ndash;2{{Clubs}} is not game forcing
*Some play that 2/1 is not absolutely game forcing and the pair can stop below game when responder rebids his suit. For example, 1{{Hearts}}&ndash;2{{Clubs}}; 2{{Hearts}}&ndash;3{{Clubs}} may be treated as nonforcing.

==1NT response to major suit opening==
Because the two-level responses are stronger than in [[Standard American]] bidding, the response of 1NT is [[Forcing bid|forcing]] for one round and is used (among other things) for weaker hands containing low-ranking suits.  Since the 1NT response is forcing, hands with a three-card limit raise can start with 1NT and later jump-support partner.  See [[Forcing notrump]] for additional details.  Some pairs play a variant in which the 1NT response to 1{{Hearts}} or 1{{Spades}} is [[Forcing notrump#Semi-forcing notrump|semi-forcing]].

Since opener has been forced to rebid on hands which he might otherwise have passed, he may have to rebid in a new suit with only three or even two cards.

==Other features==
Use of the 2/1 system usually implies (at least) the following additional agreements:
*[[Contract bridge glossary#F|Five card majors]], i.e. [[major suit]] openings require at least a five-card suit;
*Either [[Contract bridge glossary#L|limit raises]] of major suit openings (i.e. the jump raise 1{{Spades}} &ndash; 3{{Spades}} or 1{{Hearts}} &ndash; 3{{Hearts}} shows a game-invitational hand with at least four-card support) or [[Bergen raises]];
*[[Inverted minors|Inverted minor raises]], in which a jump raise of a minor suit opening is a weak preemptive bid, while a single raise is strong and forcing for one round;
*[[Jacoby 2NT]], showing strong support with 4 or more cards;
*[[Splinter bid]]s;
*[[New minor forcing]];
*[[Fourth suit forcing]] and artificial.

==Examples==

1{{Spades}} &ndash; 2{{Clubs}}<br>
2{{Diams}} &ndash; 2{{Spades}}<br>
Forcing to game, with original spade support and good club suit. This is different from standard bidding, in which such a sequence would show about 10 points, and club suit could be semi-fake.

1{{Spades}} &ndash; 2{{Clubs}}<br>
2{{Spades}} &ndash; 2NT.<br>
Forcing to game, with balanced hand and a good club suit.

1{{Spades}} &ndash; 2{{Clubs}}<br>
2{{Diams}} &ndash; 3{{Clubs}}<br>
Forcing, unless the partnership has agreed that this is an exception to the "2/1 rule."

1{{Diams}} &ndash; 2{{Clubs}}<br>
Forcing for one round only (as in [[Standard American]]), except in the variant of 2/1 where this sequence is game forcing as well.

1{{Clubs}} &ndash; 2{{Clubs}}<br>
Forcing for one round; 10 [[high card points|points]] or more with at least four clubs.

1{{Clubs}} &ndash; 3{{Clubs}}<br>
Weak; 9 points or less—sometimes much less—with at least five clubs.

1{{Hearts}} &ndash; 2{{Hearts}}<br>
Weak; 6-9 points with at least 3 hearts (unless [[Bergen raises]] are in use, in which case it shows precisely 3 hearts)

1{{Spades}} &ndash; 1NT;<br>
2{{Clubs}} &ndash; 2{{Spades}}<br>
Shows a weak hand, 6-9 [[high card points|points]], with precisely two spades.  Some also use this for an extremely weak hand (0-5) with three spades.

1{{Spades}} &ndash; 1NT;<br>
2{{Clubs}} &ndash; Pass<br>
Shows a very weak hand, perhaps 5-7 points, with at least four clubs.

1{{Spades}} &ndash; 1NT;<br>
2{{Clubs}} &ndash; 2{{Diams}}<br>
Shows a weak hand, 5-9 points, with a long diamond suit.

1{{Spades}} &ndash; 1NT;<br>
2{{Diams}} &ndash; 2{{Hearts}}<br>
Shows a weak hand, 5-9 points, with a long heart suit.

1{{Spades}} &ndash; 1NT;<br>
2{{Hearts}} &ndash; 3{{Clubs}}<br>
Shows a weak hand, 5-9 points, with a long club suit.

1{{Spades}} &ndash; 1NT;<br>
2{{Clubs}} &ndash; 2NT;<br>
Shows 10-11 [[high card points|points]] without support for spades.

1{{Spades}} &ndash; 1NT;<br>
2{{Clubs}} &ndash; 3{{Spades}}<br>
Shows 10-11 points with 3-card support for spades.

1{{Spades}} &ndash; 3{{Spades}}<br>
Shows 10-11 points with at least 4-card support for spades.

1{{Spades}} &ndash; 1NT;<br>
2{{Clubs}} &ndash; 3{{Hearts}}<br>
Shows 10-11 points with a long heart suit.

1{{Diams}} &ndash; 2{{Hearts}}<br>
This is a jump response, and there are different ways of handling it.  In [[Standard American]], such a "jump shift" shows a very strong hand and is unequivocally forcing.  However, since such hands do not occur with great frequency, it is more common today to use such a bid to show a weak hand with a long suit, unsuitable for defense.  Another possibility is to play it as a "fit-showing jump", showing 8-10 points, a decent heart suit, and good diamond support.

== References ==

===Bibliography===
* {{cite book  |last1 = Grant  |first1 = Audrey  |author-link1 = Audrey Grant  |last2 = Rodwell  |first2 = Eric  |author-link2 = Eric Rodwell  |title = 2/1 Game Force  |publisher = Baron Barclay Bridge Supply  |location = Louisville, KY  |year = 2009  |isbn = 978-0-939460-84-7}}
* {{cite book  |last = Hardy  |first = Max  |title = Standard Bridge Bidding for the 21st Century  |publisher = SQueeZe Books  |year = 2000  |lccn = 00104457 |isbn = 978-1-58776-049-5}}
* {{cite book  |last = Hardy  |first = Max  |title = Advanced Bridge Bidding for the 21st Century  |publisher = SQueeZe Books  |year = 2002  |lccn = 2002104136 |isbn = 978-1-58776-125-6}} 
 
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[[Category:Bridge systems]]