RuflRabbit, on 2019-July-03, 21:37, said:
The real problem auction is 1D - 2C, but if you can point me to any 5cM strong notrump system that's solved this problem, I'm all ears. Lawrence's Workbook on 2/1 devotes several pages to a very thoughtful analysis, but IMO, it's ultimately unsatisfying.
Is Adam's version available online?
Sorry Rufl, I missed this post earlier. As far as I know Adam has not published his version of SAYC but he has posted about it a few times on BBF so a search should provide you with the basic rules. He also tends to be very reactive and helpful to enquiries so you could also try a PM if you cannot find enough detail yourself.
The issues in the 1
♦ - 2
♣ auction can be solved in various ways. The most common these days is to make it game forcing, meaning that all of the awkward issues are contained within the 1NT response. Using some relatively idle responses such as 3
♣ to help take some of the pressure off of 1NT is helpful here.
The second approach is to retain 2
♣ as invitational or better and code Opener's rebids to sort everything out. Most systems split minimum hand types between 2
♦ (forcing), 2NT and 3
♣ while giving Opener the chance to further describe their hand after the 2
♦ rebid. It is not particularly difficult to code enough sequences to describe all hand types but it should be clear that game and slam bidding suffers somewhat in comparison to the 2/1 style above.
Finally one can make the 2
♣ response "GF except X", where X is typically one or both of a balanced invite and an invitational one-suiter. The idea of this approach is to combine the best from the two previous methods. The problem with it is that in reality you do not get the benefits of the purely GF approach and therefore need to use strategies taken from the INV+. In theory your bidding space is more optimally used in this style but it is also more complicated to get the most from that bidding space.
All of the above methods can further be simplified by using an unbalanced diamond opening and opening all balanced hands with either 1
♣ or a specialised opening (1NT, 2NT; Mexican 2
♦, etc). Not having to account for balanced hands after a 1
♦ opening effectively creates more bidding space for everything else.
In addition to the three natural approaches there are also a number of artificial schemes. Using 1NT or 2
♣ as an artificial game force over 1
♦ is quite possible. Another artificial solution is Skip Bid responses, where for example 1
♠ shows hearts. My own solution uses a 1
♥ response to show all INV+ hands with a 1NT response being weak with hearts. Sadly while these schemes have their various advantages over natural methods, all suffer from the issue of being more unfamiliar. And unfamiliarity means more complex for most players.
But the bottom line is that 1
♦ - 2
♣ need not be difficult. To my mind the auction after 1
♦ - (2
♣) is much more awkward. We have had some threads on that here at BBF and as far as I remember the most comprehensive scheme so far was posted by Hans. But that is a whole new kettle of worms.