[fromageGB]

AL78, on 2020-December-10, 16:16, said:

What do those playing three weak twos typically do with the 2♣ bid, do they open the eight playing trick hands at the one level and keep the 2♣ opening as game forcing?

Almost, but not quite. I for one play 2♣ as 9 playing tricks, and over a 2♥ denial of an A or K a 3-level bid may be passed. The 1-level open suffices with 8 playing tricks, surely?

[fromageGB]

Zelandakh, on 2020-December-10, 14:16, said:

There is some mildly interesting system discussion that can be attached to this hand...
My experience is that including 5431 shapes here is probably not a winner, tempting as it is to increase the frequency of the gadget.

My partnerships have thought that too, having once come unstuck on a 4-3 fit, and tried to accommodate that if responder picks the 3-carder, but as we can only show two suits when starting 2♣, we are concerned with losing the 3-5 fit (the 3-6 is no problem). A compromise rather than an ideal solution.

[Zelandakh]

shyams, on 2020-December-10, 19:04, said:

I recall reading about a "gadget" where someone (probably on BBF) suggested a 2♣ opening followed by a jump in major as the rebid to show 4M and 5+ m (the m can be either suit).

As per Mike's excellent post, this convention for specifically diamonds is the corollary to the conventional 3♦ call over 3♣, allowing for the effective differentiation between 4 and 5 card majors. I have never heard of it being played as either minor though - that just seems like a bad idea.

[Zelandakh]

fromageGB, on 2020-December-11, 07:19, said:

My partnerships have thought that too, having once come unstuck on a 4-3 fit, and tried to accommodate that if responder picks the 3-carder, but as we can only show two suits when starting 2♣, we are concerned with losing the 3-5 fit (the 3-6 is no problem). A compromise rather than an ideal solution.

This is a genuine concern when the fragment suit is a minor. But when the fragment is spades, as here, there is no auction where Responder is unable to show a 5 card spade suit, so only showing the other 2 suits is not really an issue. In addition, I would argue that AKQ is the worst holding to treat in this way, as ruffs in the short suit will require a top honour, reducing trump control.

So if you are going to include 5431 shapes in your strong 3-suiter Multi option, my suggestion would be to limit it to a 3 card minor and probably specifically only to (41)(35) hands that are both strong enough for slam if a fit is found in the minor fragment and not strong enough to pattern out at the 4 level.