After forcing 1NT

A response of 1NT over a 1H/1S opening shows one of the following types of hands (in case of a 1H opening, responder has denied 4 spades):

• 6-10 points, balanced, no trump support
• 6-11 points, unbalanced, no trump support
• 10+ points with trump support

In general, opener's priorities in the rebid are as follows:

• Rebid 2NT with a 5-3-3-2 hand and 18-19 points
• Rebid at 2-level with 12-16 points
  (priority: showing 6+ trumps, showing 4+ cards in the other major*, showing 4+ cards in diamonds)
• Rebid at 3-level with 17-21 points
  (priority: showing 6+ trumps, showing 4+ cards in the other major, showing 4+ cards in a better minor)

* Since 1H > 1NT denies 4 spades, no spade fit is possible. Opener rebids 2S only in case of a 5-4-3-1 hand with singleton in clubs and implies a misfit. Hence rebidding 3S can be risky in general and should only be done with 19+ points.

The meanings of opener's rebid after forcing 1NT are summarised below:

Response	After 1H > 1NT*	After 1S > 1NT
2C	12-16, 2+ clubs, exactly 5 hearts and denies 4 diamonds	12-16, 2+ clubs, exactly 5 spades, denies 4 hearts and denies 4 diamonds
2D	12-16, 4+ diamonds, exactly 5 hearts	12-16, 4+ diamonds, exactly 5 spades, denies 4 hearts
2H	12-16, 6+ hearts (continuations)	12-16, 4+ hearts, exactly 5 spades
2S	12-18, 6+ hearts, 5+ spades	12-16, 6+ spades (continuations)
2NT	18-19, 5-3-3-2 hand	18-19, 5-3-3-2 hand
3C	17-21, 4+ clubs, exactly 5 hearts	17-21, 4+ clubs, exactly 5 spades, denies 4 hearts
3D	17-21, 4+ diamonds, exactly 5 hearts	17-21, 4+ diamonds, exactly 5 spades, denies 4 hearts
3H	17-21, 6+ hearts	17-21, 4+ hearts, exactly 5 spades
3S	19-21, 1-3-5-4 (CDHS) hand	17-21, 6+ spades

* Recall that in case of 5-5 or 6-6 in majors, 1S would be opened. Hence 'exactly 5 hearts' implies 'at most 4 spades'.

While responder's 1NT bid could show a variety of hands, the exact type is usually revealed in the next bid as follows:

Responder's next bid	Type of hand shown
2NT	6-10 points, balanced, no trump support
Non-jump bid of opening major (if opener denies 6 trumps)	10-12 points, trump support
1H > 1NT > 2m > 3H 1S > 1NT > 2X > 3S 1H > 1NT > 3m > 4H 1S > 1NT > 3X > 4S	13+ points, trump support
Raising opener's second suit or bidding a new suit	6-11 points, unbalanced, no trump support