Editing Stayman convention (section)

==Standard Stayman==
After an opening bid or an overcall of 1NT (2NT), {{gcb|responder}} or {{gcb|advancer}} bids an artificial 2{{Clubs}} (3{{Clubs}}) to ask opener or overcaller if he holds a four- or five-card major suit; some partnership agreements may require the major to be headed by an honor of at least a specified rank, such as the queen.  The artificial club bid typically promises four cards in at least one of the major suits (promissory Stayman) and, ''in standard form'', enough strength to continue bidding after partner's response (8 HCP for an invitational bid opposite a standard strong 1NT opening or overcall showing 15-17 HCP, 11 HCP opposite a weak notrump of 12-14 HCP, or 5 HCP to go to game opposite a standard 2NT showing 20-21 points).  It also promises distribution that is not 4333.  By invoking the Stayman convention, the responder takes control of the bidding since strength and distribution of the opener's hand is already known within a limited range.  The opener responds with the following rebids.
*  2{{Diams}} (3{{Diams}}) denies four or more cards in either major suit.
*  2{{Hearts}} (3{{Hearts}}) shows at least four hearts (also meeting the criteria for an honor holding as may be set by partnership agreement).
*  2{{Spades}} (3{{Spades}}) shows at least four spades (also meeting the criteria for an honor holding as may be set by partnership agreement).
A notrump opener should have neither a suit longer than five cards nor more than one 5-card suit since an opening notrump bid shows a balanced hand.  A notrump bidder who has at least four cards in each major suit normally responds in hearts, as this can still allow a spade fit to be found. Variant methods are to bid the longer or stronger major, with a preference given to spades, or to use 2NT to show both majors.

In the standard form of Stayman over 1NT, the responder has a number of options depending on his partner's answer:
*  If the notrump opener names a major suit and the responder has four cards in that suit, the responder bids three of the notrump bidder's suit (invitational) with 8-9 HCP or four of the notrump bidder's major suit (game) with 10 or more HCP.
*  If the notrump bidder bids a major suit in which the responder does not have at least four cards, the responder may bid 2NT (invitational) with 8-9 HCP or 3NT (game) with 10 or more HCP.  However, if responder has 5 cards in the unnamed major, he may bid it at a convenient level in an attempt to find a 5-3 fit.
*  If the notrump bidder bids 2{{Diams}}, the opener denies a four-card major. With 4-5 distribution in the majors, the responder may bid this five-card suit with a call of 2 with 8-9 HCP, or with a call of 3 with 10 HCP.  This allows notrump bidder to find game in a major with a 5-3 split.  Without a 4-5 distribution in the majors, responder bids the appropriate notrump contract. 
Over these bids, the notrump bidder (1) with a maximum hand (17 HCP), goes to game over an invitational bid and (2) with four (or more) cards in each major suit, corrects to the previously unbid major suit.

In the standard form of Stayman over 2NT, the responder has only two normal rebids.
*  If the notrump bidder names a major suit and the responder has four cards in that suit, the responder bids four of the notrump bidder's suit (game).
*  If the notrump bidder names a major suit in which the responder does not have at least four cards or bids diamonds to deny a major suit, the responder bids 3NT (game). If the notrump bidder has four cards in each major suit, the notrump bidder corrects to the previously unbid major suit.

In either case, a responder who rebids notrump over a response in a major suit promises four cards of the other major suit. Thus, a notrump opener who holds at least four cards in each major suit should "correct" by bidding the other major suit at the lowest level.

Of course, once a fit is found, responder who has sufficient strength also may bid 4{{Clubs}} ([[Gerber convention|Gerber]]) or 4NT ([[Blackwood convention|Blackwood]]), or cue bid aces, depending upon partnership agreement, to explore slam in any of the above sequences. Some partnerships also admit responder's rebids of a major suit that the notrump bidder did not name.

A bid of 4{{Clubs}} over an opening bid of 3NT may be either Stayman or Gerber, depending upon the partnership agreement.

If an adverse suit bid is inserted immediately after a 1NT opening, Stayman may be employed via a double (by partnership agreement) or a cue bid, depending on the strength of his hand.  The cue bid, which is conventional, is completely artificial and means nothing other than invoking Stayman.  For example, if South opens 1NT, and West overcalls 2{{diamonds}}, North, if he has adequate values, may call 3{{diamonds}}, invoking Stayman.  South would then show his major or bid game in notrump.  Alternatively, North, if his hand lacks the values for game in notrump, may double, which by partnership agreement employs Stayman.  This keeps the Stayman bidding at second level.

Partnerships who have not yet learned Stayman but choose to adopt Stayman (without having yet learned or having chosen not to use Jacoby Transfers) will need to adjust their use of normal two-level responses after a 1NT opening, because the availability of this convention changes the nature of what had been normal 1NT responses. When the notrump bidder's partner does not invoke Stayman but instead calls 2{{hearts}} or 2{{spades}}, it is a sign of relative weakness (since if responder held 8 HCP or more, he would have invoked Stayman). These bids are commonly referred to as "drop dead bids", as the opening notrump bidder is requested to withdraw from the auction. If opener has maximum values, a fit, and strong support, he may raise to the 3-level, but under no circumstances may he take any other action.  This provides the partnership with an advantage that the non-Stayman partnership doesn't enjoy.  For example, a responder may have no honors at all; that is, a total of zero HCP.  His partner is likely to be set if he passes.   A non-Stayman responder would have to pass, because to bid would provoke a rebid.  But a Stayman responder can respond to his partner's 1NT opening at level 2 if he has a 6-card non-club suit.  The responder with 3 HCP and a singleton can make a similar call with a 5-card non-club suit.  This gives the partnership a better than even chance of success in making the contract, whereas without a response (and without Stayman), the contract would likely be set.

Similarly, a response of 2{{diamonds}} indicates less than 8 HCP and should usually be passed. In rare cases, when the opener has maximum values and a fit in diamonds with at least two of the top three honors, he may raise diamonds, and responder may see a chance for game in notrump.

There are many variations on this basic theme, and partnership agreement may alter the details of its use. It is one of the most widely used conventions in bridge.

===Non-promissory Stayman and 2{{Spades}} checkback by responder===

Some partnerships play that 2{{Clubs}} Stayman does not absolutely promise a four-card major (non promissory Stayman). For example, if responder has a short suit and wishes to know if opener has four-card cover in it, so as to play in no-trumps. If opener shows hearts initially, 2{{Spades}} can be used to find a fit in spades when the 2{{Clubs}} does not promise a four-card major.

1NT - 2{{Clubs}}, 2{{Hearts}} -
*2{{Spades}} = four spades, not four hearts, invitational
*2NT  = no four spades, invitational
*3NT  = four spades and game values
Alternatively 2{{Spades}} can be used for all hands with four spades and not four hearts, either invitational or game values, while 3NT denies four spades.