No-major 1♠
The 1♠ catchall denies a 4-card major. Responder holds one of:
- 4–7 without a major
- 8–11 with a splinter in a major, unless a 6-card minor jumps directly
- 12+ balanced: with no 4-card major and no 5-card minor, that is 33(43) or (32)44
A singleton ace or king is not a splinter. 8–11 hands with one bid 1NT.
Opener never shows a major with a balanced hand. Responder has at most three, so a 4-3 fit is not worth the search. A 4414 hand bids notrump as if balanced, since responder is likely to hold diamonds. Other rebids follow red transfers.
| 1♣ - 1♠ - | |
|---|---|
| 1NT | (BAL 12–14) or (11–17, 4414) |
| 2♣ | UNBAL 11–17, 5+♣ |
| 2♦ | REV, 16–20, 4+♦, 5+♣ |
| 2♥♠ | REV, 16–20, 4+#, 5+♣ |
| 2NT | (BAL 18–20) or (18–20, 4414) |
| 3♣ | 15–17, 6+♣ |
| 3NT | 18–20, 6+♣ |
After 1NT
Responder signs off in a minor or 3NT, or splinters to invite. Opener rejects with 2NT or 3♣, and accepts with 3♦ or 3NT. Notrump promises a stop in the splinter suit. Over 3♣, responder passes or corrects to 3♦.
| 1♣ - 1♠ - 1NT - | |
|---|---|
| 2♣♦ | S/O |
| 2♥♠! | INV, SPL, 0–1# |
| 3NT | S/O |
| 4NT | INV, 19–20 |
| 1♣ - 1♠ - 1NT - 2♥♠ - | |
|---|---|
| 2NT | NF, MIN, stop |
| 3♣ | NF, MIN, no stop |
| 3♦ | FG, MAX, no stop |
| 3NT | MAX, stop |
After 2♣
Responder passes with a weak hand. Opener answers the splinter as over 1NT.
| 1♣ - 1♠ - 2♣ - | |
|---|---|
| 2♦ | S/O, 5+♦ |
| 2♥♠! | INV, SPL, 0–1# |
| 3♣ | FG, 4+♣ |
| 3NT | S/O |
After a reverse
Responder plays the Blackout convention: the next step is LEB, a weak relay with 4–7. Over 2♠, that step is 2NT. Other bids are natural and game-forcing.
| 1♣ - 1♠ - 2♦ - | |
|---|---|
| 2♥! | LEB, 4–7 |
| 2NT | FG |
| 3♣♦ | FG |
| 3NT | S/O |
| 1♣ - 1♠ - 2♥ - | |
|---|---|
| 2♠! | LEB, 4–7 |
| 2NT | FG |
| 3♣♦ | FG |
| 3♥ | FG, 3=♥ |
| 3NT | S/O |
| 1♣ - 1♠ - 2♠ - | |
|---|---|
| 2NT! | LEB, 4–7 |
| 3♣♦ | FG |
| 3♠ | FG, 3=♠ |
| 3NT | S/O |