A 1NT opening is a very specific bid. All natural 1NT openings specify a balanced hand (generally, no voids, no singletons and at most one doubleton) within a narrow range of strength (generally a range of 3 HCPs). Whether a 1NT opening contains a 5-card major is a matter of preference.
- Mini notrump: 10-12 HCPs
- Weak notrump: 12-14 HCPs
- Strong notrump: 15-17 HCPs (or 16-18 HCPs)
The responses to 1NT openings are very rich with conventions, and the best set of conventions is not thoroughly agreed upon.
Natural responses Edit
- 2NT is invitational, showing 8-9 (strong 1NT) / 11-12 (weak 1NT) points and a balanced hand.
- 3NT is an obvious sign-off at game with 10+ (strong 1NT) / 13+ (weak 1NT) points and a balanced hand.
- 3-level suit bids are sometimes played as natural.
Most common conventional responses Edit
- 2♣ is Stayman, asking opener for a four-card major.
- 2♦ and 2♥ are Jacoby transfers with a 5-card suit, telling partner to bid 2♥ or 2♠, respectively.
- 4♣ is Gerber, asking for aces.
Somewhat common conventional responses Edit
- 2♠ is often a Minor suit bust transfer to both 3♣ and 3♦.
- 2♠ and 2NT---or 2NT and 3♣---or 2♠ and 3♣ are sometimes used as Four suit transfers to 3♣ and 3♦, respectively.
- 3-level suit bids are sometimes used as two-suited responses.
- 4♦ and 4♥ are often Texas transfers to 4♥ and 4♠, respectively.
- 2♠ as Minor suit Stayman
- After a negative response to Stayman, 3♥ and 3♠ may be used for Smolen transfers for game-forcing 5-4 major hands.
- Puppet Stayman to discover if opener holds a 5-card major.
- Extended Texas transfers with game-going 6-4 majors after opener denies Stayman.
Nonstandard conventional responses Edit
- 3-level suit bids may be used as splinters, showing game-forcing hands with a singleton.
- After a negative response to Stayman, 3♦ and 3♥ may be used for Quest transfers with 5-4 in the majors and invitational or better strength.
- After a positive Stayman response, 3♦ may be Stayman in doubt.
- After a positive Stayman response, 3♣ may be shape-asking relays.
When 1NT opening has been doubled Edit
Opening 1NT with a five-card major Edit
Arguments for always opening 1NT with a five-card major Edit
- Rebids will be easier (read: possible without lying)
- Game-strength hands can often recover the 5-3 fit
Arguments for never opening 1NT with a five-card major Edit
- 5-3 fits will often go undiscovered
Arguments for sometimes opening 1NT with a five-card major Edit
- Measure the value of the fit by the Law of Total Tricks (i.e. soft values in side tricks detract from total tricks, so open 1NT)
- http://www.math.cornell.edu/~belk/opening.htm - includes some examples