Distribution problem (2/1)

[655321]

1NT happily, this is not even an evil to be avoided.

 

A side benefit is that partner will no longer rebid his unsupported 5 card spade suits.

That's like saying (but with 3 fewer HCP) that you should open 1NT with a singleton regularly, with the benefit that partner will stop transferring into unsupported 5-card spade suits.

Are you deliberately trolling?

 

Obviously, if your 1NT openings never have 4 or 5 spades, and if they can only have 3 spades in a hand that would not raise partner's 1♠ response, then your comparison would be valid. But what does that have to do with anything?

 

There is a difference between auctions where partner has denied primary spade support, and those where he has not. You may believe that rebidding spades with 5 is better than passing 1NT, but I still don't see why that should cause you to miss the distinction.

[Lobowolf]

1NT happily, this is not even an evil to be avoided.

 

A side benefit is that partner will no longer rebid his unsupported 5 card spade suits.

That's like saying (but with 3 fewer HCP) that you should open 1NT with a singleton regularly, with the benefit that partner will stop transferring into unsupported 5-card spade suits.

Are you deliberately trolling?

 

Obviously, if your 1NT openings never have 4 or 5 spades, and if they can only have 3 spades in a hand that would not raise partner's 1♠ response, then your comparison would be valid. But what does that have to do with anything?

 

There is a difference between auctions where partner has denied primary spade support, and those where he has not. You may believe that rebidding spades with 5 is better than passing 1NT, but I still don't see why that should cause you to miss the distinction.

Your original post to which I replied is certainly, to an extent, circular. The point that a "benefit" of rebidding 1NT with a singleton is that partner won't rebid spades with 5 is somewhat specious, because rebidding a 5-card spade suit is, for the most part, primarily a problem because you might have a singleton. If you didn't rebid 1NT with a singleton, you'd WANT partner to rebid his 5-card major suits with a weak hand.

 

None of which is to dispute the other benefits of the 1NT rebid, which have been enumerated in other posts on this thread.

 

I agree that my analogy is imperfect in degree, because the 1NT opener may have 4 spades, while the 1NT rebidder does not, and the 1NT rebidder may have raised spades directly with 3 (though depending on your methods, the direct raise with 3 is comparatively rare). However, I have in the past run simulations comparing 1NT and 2♠ contracts where opener has a balanced hand with 2 or 3 spades, and found the 2♠ contract to be superior.

 

You may believe that passing 1NT is better than rebidding spades with 5, but I don't see why that should cause you to miss the distinction between the set of hands those where the 1NT rebids contain 2 or 3 spades, and those where the 1NT rebids contain 1, 2, or 3 spades.

[hanp]

The following double dummy simulation (using 1000 hands) may be interesting:

 

South has 12-14 HCP with an 2353, 3253, 3352, 2344, 2443, 3244, 3442, 3444, 1453 and 1444 pattern.

 

North is 5(332) with 8 HCP.

 

Neither opponent has 15+ HCP, 6+ hearts or a 7+ suits. West also doesn't have 6 spades. (a very mild condition removing some hands where there would very likely be opposition bidding.)

 

1NT by south makes on 56% of the hands, 2S by north makes on 54% of the hands.

 

Further comments: Against 2S the optimal opening lead can often be from any suit, while against 1NT the optimal opening lead is usually from only 1 or 2 suits. This may mean that double dummy analysis favors 2S contracts relative to 1NT contracts (where in practice the opening lead will more often be wrong).

 

To reflect a different style, I then reran the simulation, requiring now that opener does not have 3-card support and a small doubleton. The results were:

 

1NT makes 61% and 2S makes 52% of the time.

 

Again the lead against 1NT is more demanding than the lead against 2S.

 

As this second style is closer to my own, it seems that I should rebid 2S with 5(332) hands with 8 HCP only rarely when playing IMPs.

[hanp]

When browsing through the hands afterwards I noticed that on hands where 2S makes but 1NT goes down it is very often the case that one of the opponents has a solid overcall. To get more accurate answers I should further restrict the hands of the opponents.

[aguahombre]

When browsing through the hands afterwards I noticed that on hands where 2S makes but 1NT goes down it is very often the case that one of the opponents has a solid overcall. To get more accurate answers I should further restrict the hands of the opponents.

Alternatively, do you need to throw in the effect of allowing a balance at the 2 level when the 1NT rebid is passed around? And then the effect on the defense if 2S is bid in delay--or the possibility that the opponents play their fit at the 3-level?

 

It seems to become a question not of whether 1NT or 2S will do better on a million generated hands, but rather of whether you get a better result. I know the simulators tried to eliminate competitive hands from the opposition, but that doesn't stop them from competing --sometimes successfully.

[eyhung]

Alternatively, do you need to throw in the effect of allowing a balance at the 2 level when the 1NT rebid is passed around?  And then the effect on the defense if 2S is bid in delay--or the possibility that the opponents play their fit at the 3-level?

That's a good question, but in practice, I find I infrequently want to balance over 1m - 1M - 1NT when the opponents don't have a fit and I don't have a hand that was worth an action initially. I grant you it's certainly possible, but I don't think it's highly likely.

Responder knows way too much about opener's hand for my comfort. If someone can suggest parameters for bidding over this, it's easy enough for me to discard these hands from the opponent filter as well.

[fred]

1) Make South the only hand you constrain and give South 1453 with 12-14 HCP. I get 0.11%.

 

2) Make South the only hand you constrain and give South 2 or 3 spades, 2 to 4 hearts, 4 or 5 diamonds, 2 to 4 clubs, and 12-14 HCP. I get 3.15%. I now see that I did this wrong as far as the actual problem is concerned since I was including 2254, but I would still be interested in seeing if you get the same %s as me.

Generating 1 million hands

 

1) 0.1154%

2) 3.1474%

Cool - thanks!

 

Looks like my program works :)

 

Fred Gitelman

Bridge Base Inc.

www.bridgebase.com

[Jlall]

I think these simulations are proving that using judgment is a good idea with 5 spades when deciding whether or not to bid. Suit quality, shape, honor location, and HCP are all important factors.

[aguahombre]

I think these simulations are proving that using judgment is a good idea with 5 spades when deciding whether or not to bid. Suit quality, shape, honor location, and HCP are all important factors.

true enough. And I just noticed that the sims all assumed opening 1D with 4-4m and 3-2 or 2-3M. So people who open 1C with those cannot have 4clubs and 2 or 3 spades when they rebid 1NT. Responder with 5332 (doubleton club) knows the opps have at least 8 clubs and this might affect the decision to remove.