Our 2C opener shows about 10–15 HCP with 6+ ♣. A good 9 HCP with some extra shape is acceptable as well, especially in 3rd seat. The hand can hold a 4-card or even a 5-card major. In 3rd seat, a good five-card club suit may also be opened 2C for lead direction or preemptive purposes.
Shorthand used on this page. GF means game forcing. Inv means invitational — asking partner to bid game with a maximum; INV+ means invitational values or better. NF means non-forcing. Constructive means a hand with some values that still is not enough to invite. A puppet is a bid that orders partner to make one specific cheap bid, so the puppeteer can describe their hand next. RKC is Roman Keycard Blackwood, asking how many of the five keycards (four aces and the trump king) partner holds. NLMH means the steps answer in order: none, lowest suit, middle suit, highest suit. A stiff K is a singleton king. A shape like 6331 means those suit lengths in any order.
2♦ Artificial asking bid, promising INV+ 2♥ / 2♠ NF constructive, usually about 7–11 HCP, 5+ card suit 2NT Puppet to 3C, showing either a weak raise in ♣ (most common) or a GF 5+ 5+ hand without ♣. 3♣ Constructive up to a mild invite, usually around 8–11 3♦ / 3♥ / 3♠ Nat, 6+ card suit, GF. 3NT To play. 4♣ Preemptive 4♦ RKC ♣ 4♥ / 4♠ To play.
2♥ 4 cards in either major. 2S asks: ♥ min / ♠ min / ♥ max / ♠ max. 2♠ Maximum, no 4-card major, unbalanced or unsuitable for declaring NT. 2NT Maximum, interest in declaring NT. Bal or 6331 with stiff K. 3♣ Minimum, no 4-card major. 3♦ Maximum, 4+ ♦ Other Undefined.