[junyi_zhu]

awm, on Jul 30 2010, 09:42 PM, said:

Suppose partner opens 1NT (15-17). Let's assume partner is fairly "down-the-middle" without too many big upgrades or downgrades.

You hold a balanced 8-count. Obviously things like spot cards and honor location are important here (usual hand evaluation stuff) and need to be taken into account. But I'm curious as to what people's general strategy is at matchpoints. Do you normally invite most 8s? Pass most 8s? GF most 8s? Does it depend on your perception of partner's declarer skill relative to the field? On whether you have a four-card major?

Well, one should usually pass with most 8 HCP hands without shortness or 5 card suits. With shortness and 4 card major(s), it's probably OK to gamble with some 8 or 7 HCP hands. Of course some 8 HCP are so good that you shouldn't treat them as 8 HCP,
AT9x AT9x xx xxx, it's probably fine to push to 3NT if you don't find major suit fit, because your T9 in majors are very important. Such kind of hands are very rare though. Also, if you hold 17, then partner would pass with normal 8 HCP balanced hands, and you still think you have a reasonable chance to make 3NT, you should open 1m then.

[bluecalm]

Ok, so for example holding this hand:

---

facing 1NT 15-17 (5card major possible) we have the following results:

Opposite exactly 15count available tricks (1000 simulated hands):

tricks:
<7 7 8 9 10 11 12 13
128 208 340 246 70 8 0 0

1nt makes: 872 times
2nt makes : 664 times
3nt makes: 324 times

opposite 16-17 count:

<7 7 8 9 10 11 12 13
61 121 245 315 206 51 0 0

1nt makes: 938 times
2nt makes: 817 times
3nt makes: 572 times

Let's compare passing and inviting at IMPs non vulnerable:

a)if we face 15 count
on 128 hands passing gains 2 imps (undertricks)
on 208 hands passing gains 4imps (90 + 50)
rest of the hands it doesn't matter.

Overall: 1088 imps or 1.08 imp/board

b)if we face 16-17count
on 61 hands passing wins 3 imps (-50 opposite - 150)
on 121 hands pasing gains 5imps (90 + 100)
on 245 hands passing gains 5imps (120+50)
on 572 hands passing loses 6imps (game versus partscore)

Overall: 1419imps or 1.419 imp/board

Now we have to determine how often we face exactly 15count and how often we face 16-17. According to my simulator it's: 57.4% for 16-17 and 42.6% for exactly 15.

So overall inviting gains 0.35imp/board.

Of course at matchpoints the result will be much more convincing.

[Siegmund]

Quote

Of course at matchpoints the result will be much more convincing.

Eh?

Opposite 15, passing wins 33.6% and ties the rest -> +33.6% net
Opposite 16-17, passing wins 42.8% and loses 57.2% -> -13.6% net

57.4% of -13.6 and 42.6% of +33.6 makes pass a winner by 6% per board.

At MP, Pass>Invite, by your own figures.

You appear to have found a rare hand that is Invite>Bash>Pass nonvul at IMPs. You didn't calculate the equity for bashing, but it looks like -1.23 imps/bd opposite 15, and the same +1.42 as you showed opposite 16-17, for +.29 net vs passing. Vulnerable at IMPs, it will be Bash>Invite>Pass.

I don't recall simulating specifically a 3-2-3-5 hand with lots of tens before. It is a topic worth investigating more -- I wonder how many other examples we can find where invites are best. (If you take all 8-counts without 4-card majors as a whole, for instance, it won't be.)

What restrictions did you put on opener's hand, incidentally?

[bluecalm]

Quote

At MP, Pass>Invite, by your own figures.

Yes, sorry I am a moron.

Quote

You appear to have found a rare hand that is Invite>Bash>Pass nonvul at IMPs.

I am not sure if it's rare. I think most great 8's and flat 9's will be in that category but that's just my guess.

Quote

You didn't calculate the equity for bashin

I calculated EV of passing vs bashing so equity of bashing vs passing is the same but with reverse sign, am I missing something here ?

Quote

(If you take all 8-counts without 4-card majors as a whole, for instance, it won't be.)

I am not surprised as with most 8counts pass so much better. I think it's better to investiga bad 9's not 8's.

Quote

What restrictions did you put on opener's hand, incidentally?

Just balanced with any 5 card suit possible. 5-4-2-2/6-3-2-2 weren't included.

[Siegmund]

Quote

I calculated EV of passing vs bashing...

It looked to be as if you calculated EV only of passing vs. inviting, not of raising directly to 3NT also.

My simulations in the past did include 5422s and 6m322s, which will increase the variance - overtricks when long suit runs, down-several disasters when a doubleton is wide open - and make exactly 8 tricks a bit of a harder target. If your results are a bit more stable, that is as it should be

[PrecisionL]

I thought inviting with an average 8 hcp (no good 5-cd suit) opposite a strong NT applied only to the old strong NT, 16-18.

In the 21st Century aren't students taught to invite with 9 hcp including an A or K and maybe a ten with the honor and only with 8 hcp with a chunky 5-cd suit such as: 973 742 AJ842 Kx or 973 J42 95 AK742.

Thanks to the ACBL Daily Bulletin from New Orleans:

http://www.acbl.org/...ins/2010/02/10/ page 3

[foo]

The rule I have always taught is that an invite opposite a 15-17 1N is
a) a 9 HCP flat hand without a 5 card suit in it or
a 8 HCP hand with a 5+ card suit in it.

Judgement comes in to make sure that your HCP are actually worth what the Work Count says they are.

[bluecalm]

Quote

The rule I have always taught is that an invite opposite a 15-17 1N is
a) a 9 HCP flat hand without a 5 card suit in it or
a 8 HCP hand with a 5+ card suit in it.

Judgement comes in to make sure that your HCP are actually worth what the Work Count says they are.

Seems about right but I would change "5card suit" to "good spots". It seems 5 card suit are overrated at least my experience with simulations tells me so. Dunno how it work in real world

[jdonn]

Welcome back foo, I very much agree with your post.

[foo]

bluecalm, on Aug 1 2010, 01:42 PM, said:

Quote

The rule I have always taught is that an invite opposite a 15-17 1N is
a) a 9 HCP flat hand without a 5 card suit in it or
a 8 HCP hand with a 5+ card suit in it.

Judgement comes in to make sure that your HCP are actually worth what the Work Count says they are.

Seems about right but I would change "5card suit" to "good spots". It seems 5 card suit are overrated at least my experience with simulations tells me so. Dunno how it work in real world

The reason the 5+ card suit is important is as follows.

3N makes > 50% of the time if
a) the HCP are exactly 12+12
there are 25 HCP and an 8+ card fit
c) there are 26+ HCP and no 8+ card fit.

4M makes > 50% of the time if the above is true +and+ there is a chance to gain tricks by ruffing in the short hand (or either hand if a 4-4 fit)

a 5+ card suit in one hand greatly increases the odds of an 8+ card fit being present.

As always, the caveat that the HCP above are 7/10 A & K's, that value location is average, etc etc applies.
IOW, no "white" nor "black" magic boards.

Good sims should verify the above.

[foo]

jdonn, on Aug 1 2010, 02:23 PM, said:

Welcome back foo, I very much agree with your post.

thanks. rehi to you as well and it's good to be back.

[awm]

In general my strategy has been to pass most balanced 8s at MP scoring. Obviously there are exceptions for hands with great spots and so forth, but I'd say that I pass most of the time.

Recently I've gotten some bad results from this, although part of it has been partners opening 1NT on hands where I wouldn't (recently Kx AKx KQJxxx xx for example) so perhaps this is not wholly my fault.

Anyway, I wanted to see what the BBF action was.

[foo]

awm, on Aug 2 2010, 11:18 PM, said:

In general my strategy has been to pass most balanced 8s at MP scoring. Obviously there are exceptions for hands with great spots and so forth, but I'd say that I pass most of the time.

Recently I've gotten some bad results from this, although part of it has been partners opening 1NT on hands where I wouldn't (recently Kx AKx KQJxxx xx for example) so perhaps this is not wholly my fault.

Anyway, I wanted to see what the BBF action was.

Kx_AKx_KQJxxx_xx
is opened 1N? (!!)
With such a nice suit, this is a 1N opening only if you are "operating".

Change the hand to something like
AQ_KQx_xxxxxx_AQ
(admittedly an extreme example)
...and I have a lot more sympathy with a 1N opening.

But when ~1/2 or more (~ 5/7.5 in this case) of the hand's tricks are in one 6+ card suit, that should not be a NT opening.

[bluecalm]

If you play standard without much gadgetry you can be in trouble after 1♦ opening lacking good rebid after 1M response so I can understand opening 1NT.

[awm]

Obviously this was a case of partner trying to turn the hands. Usually a good strategy when I'm sitting across the table, but seems to have backfired this time.

Perhaps with more experience playing with this partner (not Elianna or any of my other usual partners) I'll know to invite a bit more aggressively than I usually do.

[foo]

bluecalm, on Aug 3 2010, 12:31 AM, said:

If you play standard without much gadgetry you can be in trouble after 1♦ opening lacking good rebid after 1M response so I can understand opening 1NT.

Possible Standard sequences come to mind:

1D-1M;3D
or
1D-1M;3N
or
1D-1M;4D

Some pairs use 1D-1M;2C! as an artificial "catch all" for hands with 6 D's rather than 7 for jump rebids.

...and what hand types use which sequence is Partnership Agreement.

with Kx_AKx_KQJxxx_xx
a= after 1D-1S;?? I'm bidding 3N usually.
b= after 1D-1H;?? I want to use 2C! if it is available. If not, I rebid 3D.

[lmilne]

foo, on Aug 2 2010, 09:59 PM, said:

The reason the 5+ card suit is important is as follows.

3N makes > 50% of the time if
a) the HCP are exactly 12+12
there are 25 HCP and an 8+ card fit
c) there are 26+ HCP and no 8+ card fit.

So does this mean bashing with most 12's opposite a 12-14 1NT opener? I was inviting with these back in the day when I still played weak NT, and I often invite with 12 opposite an 11-14 1NT rebid.

[Cascade]

lmilne, on Aug 3 2010, 08:35 PM, said:

foo, on Aug 2 2010, 09:59 PM, said:

The reason the 5+ card suit is important is as follows.

3N makes > 50% of the time if
a) the HCP are exactly 12+12
there are 25 HCP and an 8+ card fit
c) there are 26+ HCP and no 8+ card fit.

So does this mean bashing with most 12's opposite a 12-14 1NT opener? I was inviting with these back in the day when I still played weak NT, and I often invite with 12 opposite an 11-14 1NT rebid.

I suspect that your strategy after a 1NT rebid should be different than after a 1NT opening irrespective of your range.

The auctions

1x 1y
1NT 3NT

are much more revealing than

1NT 3NT

for identical ranges.

This seems to suggest that the opponents will be able to defend better on the first auction than the second.

On the other hand at times you will have a better evaluation of your holding on the first auction.

[foo]

lmilne, on Aug 3 2010, 03:35 AM, said:

foo, on Aug 2 2010, 09:59 PM, said:

The reason the 5+ card suit is important is as follows.

3N makes > 50% of the time if
a) the HCP are exactly 12+12
there are 25 HCP and an 8+ card fit
c) there are 26+ HCP and no 8+ card fit.

So does this mean bashing with most 12's opposite a 12-14 1NT opener? I was inviting with these back in the day when I still played weak NT, and I often invite with 12 opposite an 11-14 1NT rebid.

"An Opening bid opposite an Opening bid means We should be in Game."
An adage as old as the "Bridge hills".

So
a= if you play WNTs where a minimum 1N Opening is guaranteed to be a reasonable opening bid
(see KS for a decent systemic definition- 12+ HCP, 8- losers, 2+ Quick Tricks, etc)
and
b= if you as Responder are holding a 4+ cover card 12+ HCP opening bid,
then you should GF.

If your partnership considers sub-minimum 11's or 9 loser 12's as an acceptable part of your 1N openings, then you have to "stiffen up" Responder's requirements for a GF.

...and you sacrifice the opportunity to bid odds on 24 HCP 12+12 games.

Nothing in life is without cost.
The price for "lighter initial action" is needing more HCP between the two hands for game to be odds on.

[gwnn]

lmilne, on Aug 3 2010, 08:35 AM, said:

foo, on Aug 2 2010, 09:59 PM, said:

The reason the 5+ card suit is important is as follows.

3N makes > 50% of the time if
a) the HCP are exactly 12+12
B) there are 25 HCP and an 8+ card fit
c) there are 26+ HCP and no 8+ card fit.

So does this mean bashing with most 12's opposite a 12-14 1NT opener? I was inviting with these back in the day when I still played weak NT, and I often invite with 12 opposite an 11-14 1NT rebid.

Absolutely. I'd always bid 3NT with 12 opp 12-14 and even if partner upgrades a significant portion of 11's. I really think being in 2NT with 12+12 or even sometimes 12+13 is not a good idea.