If you have slugged your way through my preferred 2♣ method, you have discovered one large systemic bidding hole. There is no way there to show a hand too strong for an opening 2NT bid, but not strong enough for 2♣ followed by 3NT. This flaw is solved by the use of the very popular (everywhere but the US) Multi-2 Diamonds.
An opening bid of 2♦ thus includes the same kind of hands that most standard american players would open 2♣ and then rebid 2NT. For me, this shows a good 22 hcp to a very bad 25 hcp. The normal expect range is 23-24, it has to be a serious good feature to upgrade 22 or seriously flawed to downgrade to 24.
Of course, multi-2 Diamonds includes a number of other hand types besides the big balanced hand. It includes a weak two in either major, and promises six cards in the major (not five). We also throw in one other hand type, a VERY strong Acol 2 bid in a minor, promising 5 controls+ and 9.5 tricks in the minor. The reason for this is that if you open 2♣ and rebid 3 of a minor, it is game force, so that simplifies the 2♣ auctions.
Responding to 2♦ is simple. First, you treat it as a weak two in a major, and use paradox responses as defined by Chris Ryall. The basic principle is that if you would not make a game try over a normal weak two in hearts, you BID 2♥ in case that is what your partner has. The responses I like are:
- Pass = almost never occurs. must have lots of diamonds and a complete lack of hcp. Remember, partner can have 24 hcp!!!
- 2♥ = pass/correct. With a weak two, opener passes, or bids 2♠ if that is his suit. Responder may have game try in ♠ but no hope opposite hearts
- 2♠ = game try in ♥ opener can bid 3 or 4♥ with hearts, and pass with weak two in spades. Any other bid shows the opening stronger hands.
- 3♣ or 3♦ = both are natural and forcing
- 3♥ or 3♠ = Pass or correct at 3 level
- 3NT = Preemptive major raise (4-4 in majors)
- 4♣ = 4♠ and 5♥
- 4♦ = 5♠ and 4♥
- 4♥/4♠ = my suit, i don't care what you have
- 2NT = asking bid. If responder is bidding 2NT, and you have one of the big hands, slam is certain, so,
----> 3♣ shows minimum 2♥ opening (3♦ then game try in ♥'s)
---->3♦ minimum 2♠ opening, (3♥ then game try in ♠'s)
----> 3♥ and 3♠ show maximums both suits
---->4♣ or 4♦ over 2NT shows the ACOL 2 of a minor
----> 3NT shows balanced big hand (forcing after 2NT)
-----------> 4♣ baron looking for 4-4 fits
----------->, 4♦, 4♥, 4♠, 4NT show bid suits
-----------> 4NT shows clubs,
-----------> 5♣ is super gerber).
If you don't want to play multi 2♦, you can still play the 2 Club system with the three suiter, if you keep 2♦ as mexican 2♦ showing a big balanced hand with 2♥ asking for range or play the normal mexican 2♦.