Responses to 1♠
1♠ ---
1NT : 5 to poor 12 HCP. Passable by opener with min 5332 hand.
2♣/2♦/2♥ : 12+ HCP, GF, 2♦/♥ guarantee 5 cards, 2♣ guarantee 3 cards ({♣ 2 OK, but only when with ♠ fit, 3-4-4-2 shape}).
2♠ : 6-9 HCP, 3+ support.
2NT* : Jacoby 2NT. 13+ HCP, 4+ trump support, GF.
3♣* : {10-11 HCP, exactly ♠ 3}
3♦* : {10-12 HCP, ♠ 4+}
3♥* : Mini-Splinter, 10-12 HCP, 4+♠ support, unknown shortness.
3♠ : minimum
3NT : asking
4♣/♦/♥ : ♣/♦/♥ shortness
3♠ : Preemptive raise, 4+ support, weak.
3NT/4♣/♦ : Splinter, 13-15 HCP, ♥/♣/♦ shortness.
4♥ : Natural, not a splinter.
4♠ : To play.
Developments After 1♠ - 1NT
1♠ - 1NT;
2♣/♦/♥ : 12-17 HCP, natural 4+
2♠ : 12-15 HCP, 6+♠.
2NT : 18-19 HCP, balanced.
3♣/♦ : 18+ HCP, can be 3 cards if shapely.
3♥ : 18+ HCP, ♥ 4+.
3♠ : 15-17 HCP, 6+♠.
3NT : Solid 6+♠ suit, small singleton ♥.
4♣/♦ : 15+ HCP, GF, 6♠6m two-suiter.
4♥ : 16+ HCP, 6♠5♥+ two-suiter.
4♠ : To play, usually 7+ card suit.
Developments After 1♠ - 2♣/♦/♥
{
1♠ - 2♣;
2♦ : natural, not necessarily with extra value, denies ♥ 4
2♥* : relay, no fit, no ♥ stoppers
2♠ : ♠3, not minimum
2NT* : relay, no fit, with ♥ stoppers.
3♣ : ♣ 3
3♦ : ♦ 5+, no ♣ 3
3♥* : ♠ 5 ♦ 4, no ♣ 3, stopper issue in ♥
3♠ : ♠ 6 ♦ 4, no ♣ 3
3NT : to play
3♣ : no ♠/♦ fit, 6+ ♣
3♦ : ♦ 5+ (5-2-4-2 OK), no ♣ 3
3♥* : ♣ 3, shortness ♠
3♠ : ♥ 6 ♦ 4, no ♣3
3NT : to play
3♦ : ♦ fit, no ♠ fit
3♠ : ♠ 3, with good ♣
3NT : natural, generally short ♠
4♣ : ♣ solid, slam interest in ♣
3♥/4♦* : ♠ 3, showing shortness, 13-16 HCP
2♥ : natural, not necessarily with extra value.
2♠ : ♠ 3, not minimum
2NT* : relay, no ♠/♥ fit, with ♦ stoppers
3♣ : ♣ 3+
3♦ : 5-4-4-0
3♥ : ♥ 5+
3♠ : ♠ 6, ♥ 4, no ♣ 3
3NT : 5-4-2-2
3♣ : no ♠/♥ fit, 6+ ♣
3♦ : no ♣ 3, stopper issue in ♦
3♥ : ♥ 5+
3♠ : ♠ 6 ♥ 4, no ♣3
3NT : to play
3♦ : stopper issue in ♦
3♥ : ♥ fit, 14+ HCP
3♠ : ♠ 3, with good ♣
3NT : natural, generally short ♠
4♣ : ♣ solid, slam interest in ♣
4♦* : fit ♥, SPL, 12-15 HCP
4♥ : fit ♥ (maybe also fit ♠), 11-13 HCP
4♠ : fit ♠, no fit in ♥, 11-13 HCP
2♠ : default bid : either 6 cards, or
: ♣ 4+ but minimum or
: balanced but want to rightside the contract
2NT* : relay, no ♠ fit, with ♥ and ♦ stoppers (but can be weak stoppers)
3♣ : ♣ 4+
3♦* : ♣ 3, intend to play 3NT, but have stopper issue in ♥
3♥* : ♣ 3, intend to play 3NT, but have stopper issue in ♦
3♠ : ♠ 6
3NT : minimum, generally 5-3-3-2
3♣ : ♣ 6+
3♦* : ♣ 5, stopper issue in ♦
3♥* : ♣ 5, stopper issue in ♥
3♠ : ♠ 3, 14+ HCP
3NT : natural, generally short ♥
4♣ : ♣ solid, slam interest in ♣
4♦/♥* : ♠ 3, showing shortness, 12-15 HCP
4♠ : ♠ 3, 11-13 HCP
2NT : 12-14 HCP. bal
3♣ : ♣ 4+, 14+ HCP
3♦/♥* : SPL, ♣ 5+, 12-15 HCP
3♠ : at least semi solid, any value
3NT : 18-19 HCP, bal
1♠ - 2♥;
2♠ : default bid, no ♥ fit: either 6 cards, or
: ♣/♦ 4+ but minimum or
: balanced but want to rightside the contract
2NT* : relay, no ♠ fit, bad 6 card ♥ OK
3♣ : ♣ 4+, minimum
3♦ : ♦ 4+, minimum
3♥ : no ♣/♦ 4, have ♥ 2, 15+ HCP
3♠ : ♠ 6
3NT : minimum, generally 5-2-3-3
3♣/♦ : natural, 5+
3♥ : ♥ 6, good suit
3♠ : 14+ HCP, ♠ 3
3NT : minimum, bal
4♣/♦ : ♥ 5, ♣/♦ 6+
4♥ : to play
4♠ : 11-13 HCP, ♠ 3 fit
2NT : 12-14 HCP, bal, no ♥ fit
3♣ : 14+ HCP, ♣ 4+, no ♥ fit
3♦ : 14+ HCP, ♦ 4+, no ♥ fit
3♥ : 15+ HCP, ♥ 3+ fit
3♠ : solid, any value
3NT : 18-19 HCP, bal
4♣/♦ : SPL, ♥ 3+, 12-15 HCP
4♥ : ♥ 3, 12-14 HCP
4♠ : ♥ 3 and good ♠ suit
}
Competition After 1♠ Opening
(Similar to 1♥ opening.)