Doubler shows 15+ HCP and with a balanced hand generalls. Doubler's partner neither confirms nor denies a stopper in the overcalled suit suit. Minimum power doubles do not have singletons. Very strong hands can be most any shape, unless this is played in conjunction with Overcall Structure, in which case, they tend not to be one-suited or two-suited. If the hand has a little extra, a stiff honor on the side is OK. If the hand has a lot extra, a small singleton is OK.
Power doubles apply even if the 1C or 1D opening
is artificial, as in a Precision 1D or a
1C = natural or 15-17 or a Polish club. They do not apply to big clubs (e.g., strong
2C). They do not apply above the one-level. They do
not apply by passed hands, although partner can
have passed. They are very effective against
light third-seat openings.
After (1X)-Dbl-(pass)-?:
Simple suit responses: show about 0-7 points, four-
card suits at the one-level, usually 5-card
suits at the 2-level. Not forcing.
1NT response: doesn't show anything, not even a control in
their suit. Denies as much as a decent 7-count.
One may often have a choice between one of a suit
and 1NT.
2NT: 7+-9 HCP, balanced. Usually at least half
a stop in their suit.
2X: (Cue) semi- game forcing, about a good 7-count and up.
This can be done agressively, since the cards
rate to be well-placed. Semi-forcing because can stop in 4 of a minor.
Jump suit responses: invitational, 7-9, solid five-card suits.
4-level responses are natural, except that a 4-level
double-jump cue is namyats-like, in either major.
Responses to that are: 4D = interest in slam,4H =good hearts and spades, 4S = huge hand for hearts,
not so huge for spades.
3-level triple jumps are preemptive.
After (1X)-Dbl-(RDBL)-?
After (1X)-Dbl-(1Y or 2X)-?
Dbl: takeout. Can be done on shortness in the bid suit. If they have bid only one major, the double shows exactly four cards in the other major and shows nothing more than tolerance for the unbid suits. Double does not promise much in the way of values. At the 3-level, it promises values. At the 2-level, forcing partner to bid vulnerable at the 3-level requires something, but less than you think---partner has a good hand, and a weak advancer has to help out. When advancer passes, minimum PDers usually pass, too, so most of the responsibility to compete is upon advancer. Repeat, at the one-level, this does not promise any values, just the unbid major.
New suits: natural, some values, competitive, not forcing, not invitational
Cue of X: game forcing
Cue of Y: natural, forcing one round. They can psyche here, and it's effective without this treatment. Later "cues" of responder's "suit" are natural, also.
Jump cue of X: natural, forcing, good six-card suit.
Jumps in new suits: invitational 1NT: some values, some stoppers. Usually about 4-7- HCP (Rule: Free bid of 1NT shows values. Free bid of suit or shows shape.)
2NT: Natural, invitational
Rebids by the Doubleer:
2C after a new suit is artificial and shows 19-21 or so. (Good 18s shade up sometimes.) Responses to 2C are natural and non-forcing if not a jump or cue. 2C is not forcing.
2C after a NT response is Stayman.
Response to a cue-bid: New suits by doubler tend to be five-card suits except for the cheapest suit. NT promises a stopper; return cues tend to deny one.
Jumps in new suits show good strong jump overcalls.
Jump cue shows a mammoth takeout double with a void.
Jump to 2NT is a huge hand, 22-23 or so.
Raises show extra values, either by way of fit, shape, or high card. They promise at least 3-card support, usually four.
New suits after a simple suit response are five-card suits and don't promise any extra values. They are not forcing.
Cues after simple suit or 1NT responses are very strong. Herbert Negatives apply.