I make a distinction between double & bid below game or double & game.
Double & bid show doubt about strain (64,6331 etc). Double and game show half a trick over my bid.
AKQxxxxxx
x
AQx
---
over 3C i will X and bid 4S.
3C-----X------pass-------3D
???----???
3H= 6H+4S
3S=6S+4H
4H=10.5 tricks in H
4S= 10.5 tricks in S
I understand these hands do not happen often but they are imps worthy enough.
The only exception to this rules is after 4m response where my bids is either both ways or ill need to jump to show my 10.5 hands.
3D----X-------pass------4C
4H= 6H+4S
4S= 6S+4H
Quote
Well, I've actually had the auction
3D x P 3H
P 4C P 4S
all pass
and we alighted in our 4-4 fit, the original doubler had a 4216 monster.
So I certainly agree that double-then-bid is not a one-suited hand (if it were, 4S would have been a cuebid for clubs).
But you can still double first on a 3226 powerhouse, planning to pass if partner responds in and then rebids a major. It's just you'll bid 5C over 4S on the above suggested auction.
I think what has become "expert standard" is that you always have a hand with multiple-strain potential. So 3D x P 3H P 3S doesn't show a powerful hand with spades too strong to overcall, it shows extra values and, say, a 5314 distribution.
X followed by 4C=clubs and doubt about strain.
X followed by 4S= Huge hand with S.
From Psych "I mean, Gus and I never see eye-to-eye on work stuff.
For instance, he doesn't like being used as a human shield when we're being shot at.
I happen to think it's a very noble way to meet one's maker, especially for a guy like him.
Bottom line is we never let that difference of opinion interfere with anything."