Why is the rationale for requiring a minimum 5-4 distribution for an "unusual" 2NT overcall?

Question

At least, that's the understanding I got from this source on conventions (clause 4 of the "overcalls" section).

My preference is for 5-5 in the minors or the two lowest relevant suits, and a minimum of eight high card points in the two suits. If the distribution were 5-4, I'd want two extra high card points, a total of 10. Taking this way of thinking to its ultimate conclusion, I would be satisfied with a 4-4 distribution and 12 high card points.

One way of looking at it is that you need 5-5 distribution for such a weak bid. Another way is that 4-4 is "enough" if your high card strength is sufficient to compensate. To me, the 5-4 requirement is "neither here nor there." Put another way, if four cards was adequate for one suit, it should be enough for both suits. It seems like a "compromise" between the two positions. Are there "playing" reasons for such a posture (that is, are people more likely to get into trouble if they use the "4-4" standard that I advocate)? Or was "compromise" the reason this standard was adopted to make things easier for "Basic" players?

Answer 1

The convention chart document that you were reading is in no way a suggestion of how conventions should be played, or even necessarily a description of conventions that are actually played. Instead, it provides four charts setting out rules of which conventions are legal to play when the chart is in effect.

The clause you refer to is within the Basic Chart, which is intended only for limited events with beginner players. It says that an overcall of 2NT that shows at least 5-4 in the minors or in the two lowest unbid suits is legal. That also allows the much more common agreement wherein 2NT shows at least 5-5 in the minors or in the two lowest unbid suits.

Beginners will almost certainly never see this document; in my experience, most bridge players have at most passing familiarity with the laws of bridge and with additional regulations provided by national bridge organizations. If they do see this document, they must not take it as an instruction of how to bid; its only purpose is to restrict the legal bidding agreements in bridge games conducted under the aegis of the ACBL.

Answer 2

A holding of 5-4 in two suits is considered a "two suited" hand. So is a holding of 6-4, and also 5-5.

So 4 cards is considered a sufficient holding in a "second" suit. But it is not considered enough for a "first" suit (except in a three suited 4-4-4-1 distribution.

What separates a 4-4 holding from a 5-4 or 6-4 holding is that the latter two have only four and three cards respectively outside their main suits. The first has five cards outside.