From KSU to KS4G
Ronald Kalf
The main change is balanced club and unbalanced diamond.
Even though 1C is nonforcing, we respond 1D with less then 4 clubs. 1C-1D can also be up to 6 without a 4crd major or 12-15/18+ balanced as a substitute for 1C-2N. Continuations after 1C-1D include Kokish: 1H natural, fake reverse or 18-20 balanced.
Now NT-rebids by 1D-opener can be used to show both minors:
1N a minimum with 5-4/5 minors either way and including 1444.
2N value of 15-17 5-5+ (stronger hands go through 1D-1M; 2C).
1D-1N; 2C is forcing and 3C as well as 2N (with longer clubs) are minimum-bids with both minors. Opps will have at least an 8crd-fit in a major and we are sure to have at least an 8crd-fit in a minor, thus according to LoTT we should play on the 3-level.
1C-1M; 1N shows 15-18, not 15-17 and …2N 19-20. I prefer 2C good/bad rather then NMF after 1N, but keep Wolf sign-off after 2N.
SJS is no longer fashionable. After 1C we play WJS because we can play 1C-1M; 2C-2D as good/bad and 1C-1S; 2C-2H as invitational. After a 1D we do not have this luxury and play Reverse Flannery.
As 1C can be two we cannot play a standard Inverted Minor. 2N and 3C are weak with 6+, with shorter clubs bid 1D or 2C with 7-9. Opener can pass 2C with a minimum club-opening, or bid 2N with a minimum SNT. 2D replaces the normal inverted 2C-response. 1C-1N shows diamonds, comparable to 1D-2C.
As for raises of responder’s major, I have exchanged monster 6-5 or yet another game raise by invitational splinter raise (thus 1m-1M; 3M denies a splinter). First of all, there’s no follow up in B23 and IMO it’s hard to untangle. Then my partner doesn‘t like the ambiguity and last not least I’ve good experience with the splinters in my previous system. After a single raise, I play 2N as artificial, asking for shape and strength and 3m as a natural and forcing.
Reading B-7 one gets the impression that 1m-1H; 1S is almost always natural, but this cannot be true because then there would be only one „reverse“, 2om which would then have to be completely artificial. But if 1S can regularly be a fake reverse, I don‘t like responder to suppress 4crd support if weak, thus I prefer responder with a weak hand to bid 1N without and 2m with 4crd support. 2om becomes an artificial force.
1m-1S; 3S is forcing, but what should opener bid with the fake reverse? My solution is that 3N denies a stopper in om. With both stoppers opener should bid 2om. I also would prefer a fake reverse in om after 1m-1S, thus 1m-1S; 2H can only have an om-stopper with real hearts.