foobar, on 2024-January-25, 18:32, said:
Are you being obtuse? Opening 1D and using reverse Flannery does better or equal to finding the right contract in nearly every situation and you say that we'd better stick with 2N as 5m/5m?
OP has 0 invites against a 11-15 range. No way to play a part score in a major at the 2-level, or even the 3-level.
Your suggestion of opening 2D with these 5/5 hands is better but it really overloads the 2D opening. How does opener differentiate a max from a min 5/5 after (say) a 2D-2M start? Can opener show 6D/4C or not? Max 6D or not? You didn't give any continuations for this 2D opening, so hard to say what tradeoffs you are making, what you're willing to give up.
Along with virtually every natural system (e.g. Standard American), the method I proposed does just far better than either a 2D or 2N opening with these hands.
1D-1H, 2C (5m/4m either way, 2S as 4SF)
1D-1S, 2D (5m/5m, 2H as 4SF)
Yes, 1D-1S, 2D prevents you from playing 2C but the continuations are easy. If you correct to 3C then at least you have a fit and preference for clubs.
A design goal for a simple system by perhaps beginner or immediate players is not presenting them with tremendous guess situations or dilemmas in subsequent bidding.
What does responder do with GI 5S/4H after 1D-1S, 2D? Probably 2N invitational. How about GI 5S/5H after 1D-1S, 2D? Judge between 2N and 3H inv. Natural.
For each of my 1D-1M, 2m rebids I have an artificial GF at the 2-level. Not like OP's 1D-1S, 2D-3C* which is quite high.
Full credit to IMprecision as to the inspiration for this structure. The openings themselves are identical. Like IMprecision, it has two ways of raising partner's major after 1D-1M. OP's structure doesn't. No need to show 4S/5D with 1D-1H, 2D. Just rebid 1S. Sort it out with xyz. Don't cramp the bidding with another 4SF at the 3-level.
Adam or Sieong might successfully argue that their rebid structure is better. I think what I proposed is a bit simpler. Like IMprecision, it's set up for relays if the pair ever wants to add them. If they don't, they still have plenty of natural information and low artificial GFs to probe further.
foobar, on 2024-January-25, 18:32, said:
If we're comparing my (or IMprecision's) structure to other systems in which 1D-1M, 2C shows minors, then you ought to really be asking whether you have 8 or 9 cards in the minors and whether responder will know which suit to preference. If I remember correctly, IMprecision goes as far as to rebid 1N with 3145 such that responder will always know to preference diamonds with 4522. That's how concerned they are about getting to the right minor. Dealt 14(53) or 1444 one really ought to think about allowing for a rebid of 1N. It's just too easy to wind up otherwise in the wrong minor with insufficient trumps. Adam never liked my 1D-1S, 2C to show maximums with these patterns, but at least I'm showing hands that are too strong to rebid 1N. It has a purpose.
If we're comparing instead to OP's structure in which 1D-1M, 2m shows 4OM/5m then at least he's showing 9 cards and a reverser, but as I've already pointed out, it moves the 4SF bid to the 3-level. It sometimes leaves responder stitched as well. Say 1D-1H, 2C (4S/5C) and responder has 2551.
I feel like many have forgotten the strong trend we've seen by experts to require a 6-cd minor for a 2-level opening. Opening 2C with something like Axx x KJxx Axxxx isn't good bridge and it isn't something we should be recommending beginners play.