Competing through (2♣)
Interference over 1♣ follows Viking Precision 2007, with suits made natural the same way as the natural positives.
I used to frown at forcing passes, but not anymore. The strong 1♣ is unbounded in strength and shape. Using the double as a brake lets the 1♣ opener describe their hand in layers, something a limited 1NT opener never needs. Responder doubles with nothing and passes with middling values or a trap. Opener usually reopens with a relay double.
- Pass: forcing, 5–7 or a trap pass
- Double: negative, 0–4
- 1NT: forcing to game with a stopper
- Cuebid: forcing to game without a stopper
- Jump cuebid: usually the highest two-suiter
- 2NT: some other two-suiters
The notrump bids shift up over (1NT) and (2♣), as their tables show.
Over non-transfer overcalls
Overcalls with no anchor suit are treated as natural because advancer passes with that suit. The trap pass is still meaningful in holding strength and their suit.
Viking keeps its system on over (X) and (1♦). I don’t. These principles work at every level, and decent opponents put their strong hands into (X) and (1♦), which is where the uncontested system is least effective.
The only non-forcing pass is (X) P. Opener may sit for 1♣x, which may produce 200+ points in reasonable circumstances.
We drop club two-suiters over a double because they can be rebranded as traps.
| 1♣ (X) | Not TRF |
|---|---|
| P | NF: 5–7 or to play |
| XX! | NEG SOS, 0–4 |
| 1♦♥♠ | NF, 5+# |
| 1NT | FG, 8+ |
| 2♣ | NF, 5+♣ |
| 2♦♥♠, 3♣ | FG, 6+# |
| 2NT! | FG, 5+♦, 5+♠♥ |
| 3♦! | FG, 5+♠, 5+♥ |
| 1♣ (1♦) | Not TRF |
|---|---|
| P! | F: 5–7 or PEN |
| X! | NEG OPT T/O, 0–4 |
| 1♥♠ | NF, 5+# |
| 1NT | FG, with stopper |
| 2♣ | NF, 5+♣ |
| 2♦! | FG, no stopper |
| 2♥♠, 3♣ | FG, 6+# |
| 2NT! | FG, 5+♣, 5+♠♥ |
| 3♦! | FG, 5+♠, 5+♥ |
| 1♣ (1♥) | Not TRF |
|---|---|
| P! | F: 5–7 or PEN |
| X! | NEG OPT T/O, 0–4 |
| 1♠ | NF, 5+♠ |
| 1NT | FG, with stopper |
| 2♣♦ | NF, 5+# |
| 2♥! | FG, no stopper |
| 2♠, 3♣♦ | FG, 6+# |
| 2NT! | FG, 5+♣, 5+♠♦ |
| 3♥! | FG, 5+♠, 5+♦ |
| 1♣ (1♠) | Not TRF |
|---|---|
| P! | F: 5–7 or PEN |
| X! | NEG OPT T/O, 0–4 |
| 1NT | FG, with stopper |
| 2♣♦♥ | NF, 5+# |
| 2♠! | FG, no stopper |
| 2NT! | FG, 5+♣, 5+♥♦ |
| 3♣♦♥ | FG, 6+# |
| 3♠! | FG, 5+♥, 5+♦ |
Over (1NT), the two cuebids are 2NT and 3NT. There is no longer a reason to drop club two-suiters. A Wilkosz-like 2NT must be game-forcing for enough space.
| 1♣ (1NT) | Not TRF |
|---|---|
| P! | F: 5–7 or PEN |
| X! | NEG, 0–4 |
| 2♣♦♥♠ | NF, 5+# |
| 2NT! | FG, 5+♦♣, 5+ another suit |
| 3♣♦♥♠ | FG, 6+# |
| 3NT! | FG, 5+♠, 5+♥ |
Opener tries to declare suit contracts after a notrump cuebid.
| 1♣ (1NT) 2NT | |
|---|---|
| 3♣ | Consider 5♣ when we lack stoppers |
| 3♦ | Consider 5♦ when we lack stoppers |
| 3♥ | COG between 4♥ and 3NT |
| 3♠ | COG between 4♠ and 3NT |
| 3NT! | P/C COG, willing to play 4♥♠ |
Over (2♣), 2NT shows the stopper, so 3NT takes over the two-suiters.
| 1♣ (2♣) | Not TRF |
|---|---|
| P! | F: 5–7 or PEN |
| X! | NEG, 0–4 |
| 2♦♥♠ | NF, 5+# |
| 2NT | FG, with stopper |
| 3♣! | FG, no stopper |
| 3♦♥♠ | FG, 6+# |
| 3NT! | FG, 5+♦, 5+♠♥ |
| 4♣! | FG, 5+♠, 5+♥ |
Over transfer overcalls
Transfer overcalls are too many to enumerate, so two rules cover them all.
- The suit they show is the cuebid. Stoppers and trap passes refer to it.
- The suit they name is natural for us, like any other new suit.
The cuebid now comes a level lower, and its cheapest bid is the stopperless game force. Wherever the jump cuebid falls below 2NT, the useful space principle swaps their roles:
- 2NT: unusual, the lowest two suits
- Jump cuebid: some other two-suiters
- The rest follows the non-transfer overcalls.
TRAP serves as the model, where (X) shows hearts and (1♦) shows spades. (X) P stays non-forcing, though advancer seldom leaves 1♣x in.
| 1♣ (X) | TRF, 4+♥ |
|---|---|
| P | NF: 5–7 or PEN |
| XX! | NEG, 0–4 |
| 1♦♠ | NF, 5+# |
| 1♥! | FG, no stopper |
| 1NT | FG, with stopper |
| 2♣ | NF, 5+♣ |
| 2♦♠, 3♣ | FG, 6+# |
| 2♥! | FG, 5+♠, 5+♦♣ |
| 2NT! | FG UNT, 5+♦, 5+♣ |
| 1♣ (1♦) | TRF, 4+♠ |
|---|---|
| P! | F: 5–7 or PEN |
| X! | NEG, 0–4 |
| 1♥ | NF, 5+♥ |
| 1♠! | FG, no stopper |
| 1NT | FG, with stopper |
| 2♣♦ | NF, 5+# |
| 2♥, 3♣♦ | FG, 6+# |
| 2♠! | FG, 5+♥, 5+♦♣ |
| 2NT! | FG UNT, 5+♦, 5+♣ |