ye olde 3NT lead problem

[whereagles]

Here's a nice lead problem:

 

[hv=pc=n&s=st83hq752dkj843c4&d=e&v=n&b=2&a=1np3nppp]133|200|Your lead?[/hv]

 

1. Lead at IMP?

2. Would you lead differently at MP?

[billw55]

Systemic diamond either way for me. The potential for tricks is just much larger there. Tricks count at any form of scoring :)

 

I suppose that ops auction suggests that dummy lacks a major suit, and therefore is more likely to have diamonds. My hearts are just too weak for this to persuade me.

[eagles123]

Heart for me

[Endymion77]

Diamonds at IMPs / Spade at MPs for me

[mikeh]

I agree with Bill. That theory that one should lead a major on these auctions only applies, imo, if the lead is otherwise close. Here, diamonds stand out by a mile. By the way, 3N didn't absolutely deny a major. Good players bid 3N with a lot of 4333 hands with a major and good values.

[rmnka447]

Do you know what the defensive objective is when defending 3 NT?

 

Normally, it's very similar to what declarer is trying to do, namely, to set up and cash your side's long suit tricks. It's a race, but the good news is that you get the first shot. The prime considerations are how easy will it be to set up the suit and are there entries to allow cashing the suit when it's set up.

 

Start out with some counting. You're looking at 6 HCP and the declaring side has at least 25. That leaves about 9 HCP maximum for partner. There's no reason to believe that partner is in a substantially better position to set up his long suit than you are with your long suit.

 

If partner holds an honor in ♦s, it may take only one lead to set up the suit or at least a couple tricks. The ♥ Q might be a potential entry, also.

 

So, if you ask yourself the key question -- "Whose suit are we trying to set up?", a reasonably good answer is "My suit."

 

Leading a low ♦ according to your lead conventions seems right.

[Zelandakh]

Do you know what the defensive objective is when defending 3 NT?

It often depends on the form of scoring and the best way of achieving that objective can also vary greatly. Do you understand the potential difference between 1NT - 3NT and 1NT - 2NT; 3NT? On this hand I agree with the conclusion but it is also easy to understand why a major suit lead is sppealing to the other posters, especially at MP. Some world class players often prefer to lead a 4 card suit rather than a 5 card suit in these kinds of situation. Do you think they have different objectives? As an example, change the ♦J to the ♥J or change the auction to 2NT - 3NT and you might see a few more votes for a lead other than "4th highest from longest and strongest".

[Mbodell]

I choose a ♠ at IMPs and a ♥ at MP in a good field, ♦ at MP in a poor field.

 

At IMPs I'm trying to beat the contract and am assuming they barely have game values so partner has more of our values. I also assume that we are likely to be longer in the majors thanks to the auction (not a guarentee, but more likely than not, especially if they are around 25 or 26 hcp as opposed to 28 or 29 that would be even more likely to suppress the 4M in 4333). So therefore I lead the ♠.

 

In a weak field at MP I don't want to lose the board on the opening lead and "everyone" will be leading 4th best diamond.

 

In a strong field I'm not in love with leading from KJxxx in a minor, so I have to choose between the heart and the spade. It is no longer the case that I'm playing just to set. Holding them to 9 when many make 10 or 10 when many make 11 might be good enough. The risk in leading the heart is less than the diamond IMO. Maybe I should lead the spade too as there is risk from leading the heart, but we may need the tempo to get a heart trick before they run clubs and top spades, so I'll try that. Of the three situations this is the one I'm least confident is right.

[rhm]

Do you know what the defensive objective is when defending 3 NT?

 

If partner holds an honor in ♦s, it may take only one lead to set up the suit or at least a couple tricks. The ♥ Q might be a potential entry, also.

 

So, if you ask yourself the key question -- "Whose suit are we trying to set up?", a reasonably good answer is "My suit."

 

Leading a low ♦ according to your lead conventions seems right.

Wishful thinking I dare say.

Chances setting up diamonds are poor unless partner holds the ♦A and even then this will not work if either opponent holds four cards in diamonds, which is not unlikely on this bidding.

That the ♥Q is an entry in time is a little bit better than hitting the jackpot in lotto.

Of course declarer or dummy could have ace doubleton in diamonds and your partner queen third, but most of the time it is your partner, who has a singleton or small doubleton in diamonds.

This is the type of hand where double dummy simulations are an eye opener.

I have seem enough of them. I lead a major and take my zero when I am wrong.

 

Rainer Herrmann

[whereagles]

And indeed the double dummy sims led me to make an unusual lead. From sims I've seen, spade rates to be the preferred suit here, so I tried one.

 

In the actual hand it doesn't seem to matter much at IMPs, but I found it interesting that the "standard sim scenario" happened to be the one at stake, and it does make a difference at MPs:

 

http://www.bridgebase.com/tools/handviewer.html?sn=whereagles&s=ST83HQ752DKJ843C4&wn=NA&w=SAK6HT98DT2CA8632&nn=NA&n=SQJ72HK643D75CJ97&en=NA&e=S954HAJDAQ96CKQT5&d=e&v=n&b=18&a=1NP3NPPP&p=S3SAS2S5C2C7CKC4CQS8C3C9CTD8CACJC8H3C5D3C6H4S4H7D2D5DQDKSTSKS7S9DTD7DAD4HAH2H8H6D9DJS6SJH5H9HKHJSQD6HQHT

 

(By the way, how do I make that bigger??)

[Antrax]

[hv=?sn=whereagles&s=ST83HQ752DKJ843C4&wn=NA&w=SAK6HT98DT2CA8632&nn=NA&n=SQJ72HK643D75CJ97&en=NA&e=S954HAJDAQ96CKQT5&d=e&v=n&b=18&a=1NP3NPPP&p=S3SAS2S5C2C7CKC4CQS8C3C9CTD8CACJC8H3C5D3C6H4S4H7D2D5DQDKSTSKS7S9DTD7DAD4HAH2H8H6D9DJS6SJH5H9HKHJSQD6HQHT]400|300[/hv]

[rmnka447]

It often depends on the form of scoring and the best way of achieving that objective can also vary greatly. Do you understand the potential difference between 1NT - 3NT and 1NT - 2NT; 3NT? On this hand I agree with the conclusion but it is also easy to understand why a major suit lead is sppealing to the other posters, especially at MP. Some world class players often prefer to lead a 4 card suit rather than a 5 card suit in these kinds of situation. Do you think they have different objectives? As an example, change the ♦J to the ♥J or change the auction to 2NT - 3NT and you might see a few more votes for a lead other than "4th highest from longest and strongest".

I certainly do understand the distinction between the auctions you suggest.

 

My answer was pointed toward the auction OP gave, namely 1 NT-3 NT. When the opponents bid strongly to a game, normally an attacking lead is best. Then the approach I outlined is a very useful way to think about how to start defending the hand. It certainly has worked well for me for many, many years.

 

If the opponents bearly stumble into game, then that is a different situation. The focus then should generally be on not trying to give anything away. So you look for a passive lead that's unlikely to help declarer. I thought about including a comment to this effect in my original post, but decided against it to keep focused on the original situation OP was asking about.

[rhm]

If the opponents bearly stumble into game, then that is a different situation. The focus then should generally be on not trying to give anything away. So you look for a passive lead that's unlikely to help declarer. I thought about including a comment to this effect in my original post, but decided against it to keep focused on the original situation OP was asking about.

Many have given up invitational bids in notrumps when openers 1NT bid or rebid is well defined.

Anyway 1NT-3NT does not mean opponents are just below slam requirements and tricks are pouring out of every suit except one, which they have inadequately stopped.

That opponents are balanced with a combined strength close to 25 HCP is much more frequent than that they have close to 30 HCP or that they (usually dummy) have a long (minor) suit.

Not every 3NT contract is a race between declarer and the defense, where the defense has to grab the "advantage of the opening lead".

Just think how often you played 3NT after 1NT-3NT and you were looking for tricks or where the opening lead helped you to fulfill 3NT.

Matchpoints reinforces this consideration, but it holds water even at IMPs.

Anyway, whenever I lead passive I am surprised how often I hit partner's suit by accident.

The above is no exception.

 

Rainer Herrmann

[the hog]

Marston's rule - small Heart

[BillPatch]

I ran a short double dummy simulation of 100 hands using Jack. The results:

IMPs Contract set with standard low card lead:

♠ = 11%

♥ = 12

♦ = 16

♣ = 7

Best lead at IMPS is a ♦.

Defensive tricks per hand:

♠ = 2.90

♥ = 2.70

♦ = 2.77

♣ = 2.78

A ♠ lead appears best.

Kudos to Endymion77 for suggesting the winners.

[gszes]

so late both hands have been shown but I throw this into the

ring anyway. If the opps are close to 3n p rates to have

around 9 hcp so in theory it could be significantly easier to

set up a suit for p than it will be for us. Lho short in majors

is more likely to have longer clubs and if declarer has to fineese

they are more likely to finesse into partner. I would try a

 

Spade T (0 or 2) in case we get lucky and pin a spade honor in dummy.

 

no matter the form of scoring. If we miss our hand configuration is such

that there is a good chance we will get another chance to make a killing

dia switch.

[whereagles]

Genuinely surprised to see such a large difference between best lead at IMP/MP...

 

I wonder if a 5000 hands would change that (B/A do 5000 hands sims). Cutting down on standard deviation might be useful here.

[the hog]

Marston anaysed several '000 hands from major events and found that the 4 card suit was the winner.

[whereagles]

Even on such a weak suit? I'd be quite suprised in that case...

[the hog]

Even on such a weak suit? I'd be quite suprised in that case...

 

 

4 to the q is not a weak suit,Nuno.

[whereagles]

I meant "weak" as in no HHxx, no intermediates.

[chasetb]

4 to the q is not a weak suit, Nuno.

Funny you should say that. In Why You Lose At Bridge, Mrs. Guggenheim opens 1♥ on Q975 in a 4-card Majors system and 16-18 HCP 1NT, and S.J. Simon, saying only Experts should pull that off. Mind you, Marston would qualify, but for the rest of us it doesn't. I would have led a Spade for sure at MPs (Bird's book of leading versus NT and our hand strength convinced me) and would be choosing between a Spade and a Diamond at IMPs.

 

EDIT - I found my book - it was a 2443 hand with 15 HCP. Nowadays partner would likely transfer to the 5-2 Spade fit, but RHO holds ♠ KQTxx. Of course, you have a 4-4 Diamond fit with KJxx opposite QTxx, and it splits xxx-Ax

[rhm]

I ran a short double dummy simulation of 100 hands using Jack. The results:

IMPs Contract set with standard low card lead:

♠ = 11%

♥ = 12

♦ = 16

♣ = 7

Best lead at IMPS is a ♦.

Defensive tricks per hand:

♠ = 2.90

♥ = 2.70

♦ = 2.77

♣ = 2.78

A ♠ lead appears best.

Kudos to Endymion77 for suggesting the winners.

I did a simulation myself

 

2 runs, one for MP leads and one for IMP leads, each with 1000 deals.

 

Specification

 

East: (15-17) balanced, 5 card major possible

West: (9-15), not necessarily balanced, at most 3 cards in each major, except when 4M333.

 

Result:

 

IMPs: Contract was beatable double dummy on 258 deals (26%)

 

Number of deals in brackets how often a specific South card as opening lead would beat the contract:

 

♠T (123) ♠8 (128) ♠3 (125) ♥Q (80) ♥7 (123) ♥5 (124) ♥2(124) ♦K (108) ♦J (101) ♦8 (142) ♦4 (148) ♦3 (148) ♣4 (108)

 

MP:

 

Number of times a specific South card as opening lead would provide most tricks to the defense:

 

♠T (659) ♠8 (669) ♠3 (667) ♥Q (493) ♥7 (659) ♥5 (662) ♥2 (662) ♦K (394) ♦J (407) ♦8 (487) ♦4 (498) ♦3 (498) ♣4 (632)

 

My Conclusion:

 

There is not much to choose between a spade and a heart lead.

A diamond lead is terrible at Matchpoints. In fact it is worse than any other lead except the ♥Q

 

At IMPs it is close.

While a low diamond lead beats the contract more often than any other lead, the difference compared to a major suit lead is not earth shattering, 12.4% versus 14.8%, a 2.4% difference.

However, you often will lose a trick when a diamond will not beat the contract.

The 2.4% of times you beat the contract more often, and win 11 IMPs has to be balanced against the 16.5% of times where you will lose one or more IMPs in tricks.

 

Rainer Herrmann

[Zelandakh]

IMPs: Contract was beatable double dummy on 258 deals (26%)

♠T (123) ♠8 (128) ♠3 (125)

 

MP:

♠T (659) ♠8 (669) ♠3 (667)

Anyone else find it interesting that the best spade in either case is the 8 from T83? Is that a mini-win for 2/4 or Busso over 3/low? Anyone got a list of holdings where the traditional lead is often wrong?

[billw55]

Anyone else find it interesting that the best spade in either case is the 8 from T83? Is that a mini-win for 2/4 or Busso over 3/low? Anyone got a list of holdings where the traditional lead is often wrong?

I think difference is small enough to consider that a coincidence.

 

I am however, astonished by the difference in total tricks between a spade and a diamond.