Suction Over Big Club
After an opponent opens with a big 1C or 2C, suction intervention uses all suit bids - at any level - for one of two possibilities, either: 1) a one-suiter that is one step above the intervenor's bid, or 2) a touching two-suiter in the next two suits. Suction usually uses a double of a club opening in a similar manner, either: 1) a diamond one-suiter, or 2) a major two-suiter. A notrump bid - at any level - is used for non-touching two-suiters, either: 1) the "round" suits (H & C), or 2) the "pointed" suits (S & D).
It will be up to the intervenor’s judgement as to what level the intervention takes place, e.g., with a hand worthy of a weak-2S opening, after an opponent’s big 1C or 2C opening, a suction 2H might be used. With a minor two-suiter worthy of an unusual 2NT overcall, after a big 1C or 2C, then 2H could also be used. With a good 6- or 7- card diamond suit, or a major two-suiter worthy of competing at the 3-level after a big 1C or 2C, then 3C could be used.
Suction should still be in place after a club opener's partner makes an artificial response like 1C-1D or 2C-2D, or for that matter, even after other artificial sequences like control-showing 1C-1H or 2C-2H, so long as the response is not natural, i.e., when it discloses no distribution information. A double of an artificial response shows either a single-suiter that is one step above the response or the touching two suits above that.
The advancing partner of the suction bidder should try to further the preemption when possible. After 1C-2H (spades or the minors) for example, if the suction advancer happens to have 4-card spades with 4-card clubs, then a bid of 4C might be warranted. The suction bidder would then pass 4C when holding a minor two-suiter, else correct to 4S with a spade one-suiter. After 1C-2S (either a club one-suiter or a red two-suiter), if the suction advancer happens to have 4-card clubs with only 3 cards in one of the red suits, then a bid of 3 of the 3-card red suit should be best. The suction bidder would then pass when holding a red two-suiter, else would know to correct to 4C with a club one-suiter.
Advancing after a suction NT overcall may necessitate a bit of care. After 2C-2N-P, give the advancer:
x
Qxxxx
xxx
xxxx
He has to be pessimistic. If his suction-overcalling partner has hearts & clubs, then advancer's choice would be hearts (likely 4H). But if he bids hearts over 2NT and his partner turns out to have spades and diamonds, then a correction to 3S would come next, necessitating advancer's bid of 4D which would likely be too high. So advancer's practical choice is 3D. If partner then corrects to 3H, then all will be well, and perhaps he'll then consider a belated 4H.
Keep in mind that there are two possible distributions for every suction bid. When a suction-overcaller bids a suit, the one thing he should not have is length in the suit that he is actually bidding.
Many suction players use double in the manner described above. But its nuisance value over a 1C opening is small. If used in this way, it could imply some strength with a desire to contest for the contract. Alternatively, double could be used as lead-directing, and if just trying to preempt the stronger opponents, then 1C-2C or 1C-3C or 2C-3C could be used for diamonds or the majors.
x double = a diamond one-suiter or a major 2-suiter
♦ a diamond bid (at any level) = a heart one-suiter or a black two-suiter
♥ a heart bid (at any level) = a spade one-suiter or a minor two-suiter
♠ a spade bid (at any level) = a club one-suiter or a red two-suiter
♣ a club bid (at any level) = a diamond one-suiter or a major two-suiter
• a NT bid (at any level) = a non-touching two-suiter: either the "round" suits (H & C), else the "pointed" suits (S & D)