Types of Stayman Enquiry Opposite 1NT

Overview

The most common use of Stayman is where responder has invitational or better values and at least one 4-card major.

But there are a number of other types of much weaker hand where we still employ Stayman:

• hands with both a 4-card and a 5-card major, where responder passes a major-suit response, and bids two of his/her 5-card major over a 2♦ rebid
• hands with a 4-card major and a 6-card minor. Here responder checks for a 4-4 major-suit fit, over 2♦ passing or signing off in 3♣
• hands with two 4-card majors and a 5-card diamond suit. In this case responder passes any rebid from opener. Responder may follow this route even if not quite 4-4-5-0 shape, thinking that any rebid from opener will result in a better spot than 1NT.
• hands with two 4-card majors. Hands like this are treated like having nine cards in the majors, but in this case responder bids 2♥ over a 2♦ rebid. Opener has to be aware of this possibility, and will correct to 2♠ with a doubleton heart and three spades.
• hands that don't have both majors, but where responder feels that to pass 1NT would lead to a poor result.

Most of us would employ the first and third  of the above options. The meaning of a 2♣ Stayman enquiry followed by a 3-minor-suit bid needs to be explicitly agreed with partner, but this is how we play it.

The fourth of the above options is how we play it, but see Andrew Robson's article covering both this specific hand-type as well as variations on the theme.