[hylins]

In the previously posted (Sept 6, 2020) TRANSFER style responses to the strong 2C opening,
the responses fell into two categories, balanced hands and unbalanced hands.
There are, however, 3 possible types of unbalanced hands to deal with.

(1) 1 single 5+ suit
(2) 2 suits 55 or better
(3) 3 suits (4441)

With only 8 bidding steps between 2C and 3NT, the responder will be very lucky to have a chance to show the 2nd suit under 3NT, and almost impossible the 3rd suit in the 4441 case.
To better use the bidding space, the 2♥ bid can be designated to show both cases (2) or (3).

Therefore, the new improved responses to the strong 2C opening become

2D 0-4 Hcps, Negative
2♥ 4+ Hcps, GF, 2 suitors (55) or 3 suitors (4441)
2S 4+ Hcps, GF, balanced hand
2N 4+ Hcps, GF, 5+ card Club
3C 4+ Hcps, GF, 5+ card Diamond
3D 4+ Hcps, GF, 5+ card Heart
3H 4+ Hcps, GF, 5+ card Spade

After 2C-2♥, the opener will bid
(a) 2S/3C/3D/3H to show the 5+ card suit.
(b) 2NT/3NT to show the 22-24 or 25+ balanced hand.


The responder’s next bidding for case (a) can be shown with the help of 2C-2♥-3D example.

3H 4-6 or 10+, S+C 55 (Not D or H, the other 2 suits)
3S 4-6 or 10+, C+H 55
4C 4-6 or 10+, H+S 55
4H 7-9, S+C 55
4S 7-9, C+H 55
5C 7-9, S+H 55
3N 4-9, 4414
4N 10+, 4414
4D 8+, Dx3+
5D 4-7, Dx3+


The responder’s next bidding for case (b) of 2C-2♥-2NT/3NT can be a little bit complicated.
I like responder's 3C/4C for 4441 with various strengths, while bidding a suit at the lowest level
in transfer style to show 55. That is to say, 3D means H suit plus C/D/S suit 55.

I will leave it to your partnership to define your preferred responses if you like this 2C-2♥ convention.
Have fun!

[mycroft]

Anything that assigns 2NT by responder to a hand more likely than not to play NT (3, or 6) is an auto-fail in my book. That's the reason the "2♥ immediate ultra-negative" crowd uses 2NT to show a long, strong major: "Despite your hand, we probably want to play in my suit" (especially when you have the big balanced 2♣ opener); that's also the reason that 2NT isn't used for "4+, any 5-card [major]".

2♣ openers (should) come in two flavours:

• Big Balanced hands
  
• Strong one-suiters (rarely two-suiters)

The Big Balanced hands, where opener needs to know responder's shape, already have a decent system to have that shown, there's no real reason to learn a new one. The unbalanced ones don't want to get shape (mostly), they want to get fit and controls. The issue here is that this is a solution in search of a problem. It's a very nice solution, I will admit.

Also, like I said the last time, the reason for transfer responses is to get the big hand to play your suit. For that to be right, the chance of responder stepping on opener's suit has to be less than the chance of playing in responder's suit. In my Precision system, with 16 opposite 8 (+ on both sides), that's quite likely, and I do play transfer responses. In a standard system with 22 opposite 4 (less likely to be + in either hand here), the chance we want to play in the weak hand's suit over the strong hand's suit is much lower, enough that it does run up against "loses more than it wins".

If you're interested in this kind of thing, you should look at Berkowitz-Manley _Precision Today_, or Symmetric Relay if you want to go whole hog, or the like, and see how "shape and control relay" is handled there. It's a lot of fun, and useful. Just not here.