In fleshing out a basic set of rules for S1N, one of the main things to decide is the systemic approach as to how to show shortage (and length where relevant, though it’s not a relay system per se, so this is slightly less relevant). I come from a relay background, so that is the preferred approach for me, but many people use substitution, or a mix of substitution and relays: often, because they don’t consider it from an overall system and memory perspective.
To illustrate what I mean, let’s consider the hypothetical auction 1♠ 2♠ 2NT, where 2NT asks about responder’s shape. Let’s also assume in this hypothetical auction that 3♣ would should a balanced hand and that 3♦through 3♠ need somehow to show shortage. You’ve got at least four options: I’ll put them in my order of preference
- Relay style: Shortage down the line (and, where relevant, length up the line, though some, perversely in my opinion, don’t regard this as an essential complement)
- Transfer substitution style
- Relay style: Shortage up the line
- Simple substitution style
Let’s look at (4) first. In simple substitution, bids describe something about the suit bid. So here, 3♦ would show a diamond shortage and 3♥ would show a heart shortage. 3♠, the trump suit, acts a substitute for the unavailable 3♣ bid and shows a club shortage. It’s pretty clear to me this is poor as over 3♦ and 3♥, the opposition have a clear chance to double (where it is for a lead, or for to suggest a sacrifice, of both, doesn’t matter: it’s easy for them).
Looking at (3) next, shortage up the line, at first glance it doesn’t appear too bad: 3♦ shows club shortage, 3♥ shows diamond shortage and 3♠ shows heart shortage. However, imagine a hypothetical 1♥ 2♥ 2♠ auction. Now all the shortages line up with the bid suits: not good. You are then faced with the choice of accepting this, or creating an exception, which gives its own set of memory problems.
Transfer substitution, no (2), improves on simple substitution. You can play it transfer up or transfer down: here I’ll assume transfer up. So, 3♦ shows a heart shortage and 3♠ shows a club shortage. 3♥ acts for the unavailable 3♣ bid and so shows a diamond shortage. There’s nothing fundamentally wrong with this approach other than being slightly more difficult to remember that some other methods (also, occasionally you get the problem where there are two substitutes required, necessitating a rule to determine which to apply to which missing bid).
My preference is of course (1), relay style, shortage down the line. In this case, that gives us 3♦ showing a heart shortage, 3♥ showing a diamond shortage and 3♠ showing a club shortage. So, no coincidence of suit bid and shortage. Even in the 1♥ 2♥ 2♠ hypothetical auction, this remains true. Some fairly basic mathematics will tell you that in this type of scheme, you will have at most one bid coinciding with the suit shown, and often none, as in the two examples above. Hence, an easy to apply rule with little or no need to memorise exceptions.
Interestingly, I learned relays length down, shortage up. I think this is an understandable but unfortunate extension of wanting to shows the majors first. I don’t intend to go back!
Regards, BM