Vampyr, on 2020-November-11, 06:16, said:
Who is "we"? I play Multi-Landy with all of my partners. (But see below). So two defences is more than I need. But if I weren't happy with any of the defences that someone else has come up with, I would devise my own and now there would be at least 71.
Over a strong NT, with some of my favourite partners I play a version of Meckwell that is possibly unique. So actually there are already at least 71.
No need to be arch. 'We' is the Bridge-playing public at large. Although, to be fair interference over NT is something that is generally learned systematically at intermediate+ level. And then only by established partnerships.
Given that during lockdown when all the Clubs were closed, and BBO was almost the only game in town it might be possible to look back and estimate just how many intermediate+ players there are in the world.
I take your point about strong vs weak. I seem to recall reading recently that Cappelletti was originally designed for use over weak 1NT yet it's what GIB uses, and it's very louche in worrying about its holdings.
I've had cause to call the Director many times in Robot tourneys

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Agree with Mycroft. You shouldn't bid 2♣ if partner would disapprove; and if you sometimes bid 2♣ with 4-4 in the majors, then you should change your explanation and system-card.
If partner would bid a major with 4-cards but bid 2♦ when 2-2 or 3-3 or 2♠3♥, then it is better to hold ♦ than ♣ length because you can take a view and pass 2♦.