Legality of a varying strength 1 of a suit
I'd like to ask about the legality of methods in which a 1-of-a-suit opening bid shows different strengths according to different hand types, as it's a situation where the rules in the Blue Book are insufficiently objective to be easily applied. This is focused on games which are limited to partnership understandings available at level 4.
As a simple example of the sort of situation I mean, many people play "rule of 20", i.e. a 5=4=2=2 or 6=3=2=2 hand can be opened on 11 HCP, but a 5=3=3=2 would require 12 HCP to open, even if all these hands are opened with the same bid (e.g. 1!s). Presumably this is entirely legal, as it's one of the most commonly seen methods in club play.
My issue is that I'm unsure how far this sort of method can go before it violates rules like "A pass before any player has bid must not show, or usually have, any values" (Blue Book, paragraph 7A2). It's certainly plausible to argue that if a 5=4=2=2 hand with 11 HCP is treated as having values (and thus opened), a 5=3=3=2 hand with 11 HCP should also be considered to have values, and thus passing it is illegal. However, I think that the reason that passing the 5=3=3=2 hand is considered legal is that passes usually show less values than this; the passed almost-opening-hand is rare and unexpected as passes go, with weaker hands being much more common.
So my specific question is how to interpret the "usually" in "usually have". For example, would methods in which all 1=4=4=4 hands and 2=2=3=6 hands are passed on 11-15 HCP be legal? The frequency of these "unusual passes" is considerably higher than for equivalent passes in more standard methods, although still fairly low compared to the frequency of a pass that does not show values. Is there some defined cutoff point at which passing a hand that's typically considered to be opening strength is considered legal? (Likewise, is there some defined cutoff point above which any hand must, by partnership agreement, be considered to be worth an opening bid? Or can even some very strong hand types be initially passed, by partnership agreement, if they occur rarely enough that any particular pass has a low probability of containing values?)
There's also the opposite situation, in which some hands are opened as 1 of a suit when weaker than other hands that qualify for that bid. For example, is it legal to have methods in which 1-of-a-suit opening bids normally show 12 HCP, but can have 10 HCP if they have two 4-card majors (a considerably weaker hand type)? Again, the only rule that this could potentially fall afoul of is the "passes cannot be strong" rule, but it's not worded objectively enough to be able to apply it.
Comments
I don't see in any of your examples that values are shown by the pass. I think the reason it isn't more tightly defined as to what "usually have" means is that this is not a problem that ever arises in practice. If it did, we would just have to make a judgement based on the specific situation.
What the regulation is seeking to avoid is methods where a given hand is 1-level bid but replacing a card by a larger (honour) card in the same suit makes the hand an opening Pass.
That's a good way to think about it (and would rule out all strong pass systems for obvious reasons). Thanks for helping to clear this up for me.
I like Robin (BarkerBridgeTD)'s explanation.
It may also help if I explain where the wording of this regulation came from: we used just to say that a pass cannot promise values, but then a system was suggested where you could get round this by playing that a pass shows, for example, either 9-14 or 4333 0-5 with all four twos.
There was at one point some popularity for playing, NV, that you open all 0-6 hands at the 2-level in your longest suit which means that pass promises 7-11. Without getting into a separate discussion about whether that ought to be allowed, the L&E decided it shouldn't.