jdonn, on Dec 15 2009, 03:04 PM, said:
So it was every suit, not just clubs. I guess I remembered that because awm's example was in clubs.
Actually, it's not true in every suit. While I was able to get similar results as awm for a 1C opening (similar parameters to awm except opener is allowed to have a 5cM with 6+ clubs and a good hand, and some balanced hands are discarded due to opening NT ranges), it's not true for a 1H opening (which guarantees 5 hearts, and also can't be 15-17 balanced or 20-21 balanced, and might have 5 spades only if holding 6+ hearts).
When RHO opens 1H and you are considering overcalling 1S, if you hold
4=2=3=4 shape
Over 1 million deals, partner averages 3.39 spades and RHO averages 5.52 hearts
4=4=3=2 shape
Over 1 million deals, partner averages 3.45 spades and RHO averages 5.30 hearts
This seems slightly unintuitive given awm's argument, so I'd appreciate it if someone else could double-check my results. If they hold, the only explanation I have for this discrepancy is that RHO's club length has far more variance. With long clubs in the overcaller's hand, the results are therefore weighed towards the short club openings, which significantly and adversely impacts partner's spade length. But when you are long in hearts, RHO's minimum is always 5, and usually in the 5-7 range,
Taken to an extreme, let's say RHO is playing a system where 1H promises 9 hearts. Now, with 4-4 in the majors, you know partner has exactly 0 hearts so he is longer in spades than if you were 4-2 in the majors.