Liversidge, on 2015-December-05, 14:29, said:
I have had a good look at Rubensohl and I so far I do prefer it to lebensohl, for several reasons (transfer, ability to show your suit right away in case of intervention).
When you mention "refinements" does that include a modification to Stayman where a response of the overcall suit prioritises the lack of a stop over the presence or otherwise of a four card major? I came across this from one source and although it adds another layer of complexity maybe its worth learning / adopting from the start.
There are several extra things you can do. The first one is better defining the follow-ups. In the case of the Stayman sequences, the easiest is for the cue (first step) to deny a
known major fit or a stopper, while 3NT denies any
possible major fit and shows a stopper. The difference between the 2 italicised words is seen after an overcall showing diamonds:-
1NT - (2
♦) - 3
♣ = Stayman
===============
3
♦ denies a diamond stop but does not deny a 4 card major
3
♥ shows 4 hearts and a stopper
3
♠ shows 4 spades and a stopper
3NT denies a 4 card major and shows a stopper
The point is that Opener does not know which 4 card major Responder holds in this case so passing stopper information first makes sense. The corrolary to that is that it is possible to refine the structure further for Stayman to be non-promisary and also cover the 3
♠ (stopper ask) response. The problem with that is that it means different structures for different overcalls - that is not only a bad idea for N/B/I players but also provides minimal advantage.
Perhaps more important would be follow-ups to a double, specifically double then bid sequences. The simple form of this is to cover the unavailable invitational hands this way, so that (for example) 1NT - (2
♠) - X; 3m - 3
♥ shows an invitational hand with 5+ hearts. But it is also nice to be able to use some of these sequences for 2-suited takeouts - modify the auction slightly to 1NT - (2
♠) - X; 3
♣ - 3
♦ and now both an invite with diamonds (and heart tolerance) and competitive with both red suits are interesting hand types. There is a solution to this too but it adds a fair amount of extra complexity and removes one of the advantages of Rubensohl. Basically the 2NT response is underloaded showing clubs so it is possible to add the extra invites here. Taking a natural 2
♠ overcall as the examples again:
1NT - (2
♠) - 2NT; 3
♣
==================
3
♦ = natural invite
3
♥ = natural invite
other bids show clubs
Again, the benefits you get compared to the extra complexity are small but for pairs looking to fully optimise it probably makes sense to do this. Further refinements are possible too. For example, PK has often pointed out that the take out double can handle most Stayman hands if you are clever enough with your follow-ups so the Rubensohl Stayman sequence can be used for something else. That is probably correct but is also not something I would suggest to non-experts.
As you can perhaps see, most of the refinements mean squeezing out the maximum from the possible sequences at the cost of complexity. For many of them the advantages are so minimal that I prefer not to use them myself. For N/B players, the benefits just from playing the simplest form are already so large that the danger of making a mistake through extra complexity is really not worth it. Much better to put those efforts into other areas imho.