Bob Munson

Which major do you lead vs. 3NT?

Last month’s blog featured a hand where I led the 10, unsuccessfully, from Q102 vs. 3NT.  At the time, I thought the 10 was the right lead, but it just didn’t work out this time – a standard psychological ploy we all use to deceive ourselves when we don’t want to admit errors.  But, I did some further research and decided it was time to point out (via this blog) that the 10 was wrong, and develop some better ‘rules’ about what to lead when.

I’m going to focus on auctions where you are going to lead a major and have to choose between a 4 card major and a 3 card major (if you happen to hold a side club suit such as AKQJ42, the traditional J ‘4th from longest and strongest’ will likely be a more effective lead than a major suit, but I’m assuming some different minor suit holding).  What are the auctions where you are going to lead a major?  Here are some, although this is not an exhaustive list.

West
East
1NT
3NT
West
East
2NT
3NT
West
East
1
1
1NT
3NT
West
East
1
1
2NT
3NT

I have made numerous references, in the past, about David Bird’s groundbreaking work in his book Winning Notrump Leads.  Unfortunately, that book can provide some guidelines regarding hundreds of sample hands, but it does not include every hand you will ever be dealt, so additional research is possible using Lead Captain by Bob Richardson.

http://www.bridgecaptain.com/LeadCaptain.html

With Lead Captain, you can enter any specific hand for the opening lead and then describe what you believe the cards should look like for dummy and declarer based on the bidding (you can include a description of partner’s hand too, but often, partner was not bidding so they get random leftovers).  Then you can run a simulation that randomly deals the remaining 39 cards and selects all deals that conform to your description of the other hands.  Once a hand is selected, every card is analyzed as a potential opening lead and, from there, the hand is played double dummy.  The result shows the % of time that a particular card is successful (obviously comparing leading this card vs. leading that card).  In finding the best lead, David Bird used a threshold of 5000 deals (out of millions) that fit his parameters for dummy and declarer.  With Lead Captain, I usually use 10,000 deals (because it doesn’t take very long), but you can select any number you want.

So, I held, as reported in my last blog:

N
 
9764
Q102
AJ1042
3

 

 

The auction was the third one in the list above (1-1-1NT-3NT).  Why did I think the 10 was the right lead on that hand?  Two reasons.  I drew invalid conclusions from the David Bird book (when faced with 4-3, ‘always’ lead the 3 card suit).  And, earlier in the day, another hand, not reported in the blog had been played with auction #4 (1-1-2NT-3NT) where my partner, holding the hand below, led the 2 when the K would have defeated the contract (further cementing my notion of ‘always lead the 3 card suit’).

N
 
A742
KQ8
1097
654

 

 

Anyway, I came home and ran Lead Captain, ‘knowing’ that it would ‘prove’ my 10 was the right lead!  It didn’t (thus, the motivation to create this blog).  At first I thought I merely described dummy and declarer incorrectly, because the  10 just had to be the right lead.  Then I learned something.  I asked Bob Richardson what I was doing wrong and he said: “nothing is wrong – the 10 is not the right lead!  The  10 was ineffective because of the tenace in hearts.”  Spades were safe (it gives nothing away), while the heart lead can (and did) give a trick away.

First, where did ‘lead the 3 card suit’ even come from?  ‘Everyone’ knows you lead 4th best from longest and strongest.  David Bird pointed out that the real objective when defending against 3NT is scoring 5 tricks, and 5 card suits can be the most effective at achieving that.  If you lead a 3 card suit, partner is more likely to hold 5 in that suit than if you lead a 4 card suit.  So, you are often off to your best start to defeat the contract when attacking the 3 card suit.  I should warn that the statistically best lead over 10,000 deals won’t always be the best lead from that hand on a given deal.   You won’t hold that hand with that auction 10,000 times in order to reap the benefits of the law of averages.  Still, learning to make the best lead can be a useful skill to acquire at the bridge game.

For those not familiar with David Bird’s book or Lead Captain (which is really David Bird’s book written in software), one surprising theme comes up repeatedly.  That is, an out of the blue lead of an unsupported ace is a winning lead – one that traditionally would never be made at the table.  How can that be?  The answer lies in double dummy defense.  After leading the ace, you can switch, at trick 2, to the card you should have led and still be successful in the defense.  But this only works with sufficiently accurate signaling (and reading the signaling) to get the subsequent defense right.  Of course, in double dummy defense, signaling is irrelevant.  The defenders always make the right play, the right shift.  David Bird addressed that issue in his book (concern that double dummy defense isn’t realistic).  He points out that both sides (defense and declarer play) get the benefit of double dummy.  Sometimes the double dummy play would not have happened at the table.  But, when considering 10,000 deals, it all averages out and the results are valid.

When I ran the simulation for the second hand above, the A got the top prize as it would have at the table.  Win the A at trick 1, shift to the K and you can establish partner’s heart suit while they still have their entry.  Leading unsupported aces still remains quite dangerous because you are giving up a tempo, potentially establishing declarer’s tricks before you establish your own.  You may need that entry later.  But, on that hand, using Lead Captain, the K stands out as far better than a small spade lead.

So, now I’m going to share some of the hands that I researched.  Assuming one of the auctions above (or any other auction) has led you to decide to lead a major, and you are 4-3 in the majors, which one do you lead?  The numbers reported below show the % of time that that lead would defeat the contract.

Starting with my actual hand that caused me to write the blog:

 
 
9764
Q102
AJ1042
3

 

7 was best at 43.3%  3 was 37.2%  10 was 34.8%

Lead any spade and that lead will be better than any other suit, but specifically the 7 was the best spade to lead, conforming to standard practice of leading second best from 4 small.  The 9 is small, but it isn’t that small – it can come into play later and should not be wasted at trick 1.  Next up was the lowly 3, leading right into declarer’s bid suit – a surprise to me, but since you are so short in clubs, sometimes partner will be long.  And the club was better than leading that heart tenace!  The 10 was the best heart to lead (since, if you do hit partner’s suit, you may need to start unblocking/getting out of the way of his suit at trick 1), but as noted repeatedly above, hearts is not the best way to start the defense with this hand.  A diamond lead was a distant fourth place.

Now, changing the hand to take away the heart tenace

N
 
9876
987
AJ1042
3

 

9 was best at 36.7%, but the 9 was close behind at 35.7%

Here, the heart lead is best, but barely.  It is close to a tossup.  I expected the 3 card suit to be much better than the 4 card suit,  but the simulation indicated it didn’t much matter which major was led, just be sure to lead a major.

Now I wanted to beef up the heart suit, thinking that would make a huge difference

N
 
9764
J109
AJ1042
3

 

J was best at 40.3%, but the 7 was not far behind at 38.3%

This was the most shocking run of all, since the texture of hearts seems to me to make a heart lead an overwhelming choice for the opening lead instead of barely beating out  a spade lead.  Still, the results are what they are.

 

Another hand, balanced, with a weaker heart holding, but includes the A.

N
 
A752
1094
QJ3
742

 

10 was best at 33.6%, clubs were 29.4%, small spades 28%

Surprisingly, the A came in worse than the small spades – 27.1%, the worst spade of all (but still better than leading diamonds!).  I think the reason leading the A was so bad here vs. when holding the KQ8 is that the weaker hearts made the loss of tempo (by leading the  A) devastating.

 

What if both major suits have a dangerous tenace?  Which one do you lead?

N
 
KJ76
Q102
AJ1042
3

 

3 was best at 38.5% 6 was next at 34.5% and the 10 came in at 33.5

Not what I was expecting.  Here, the passive club lead beat out both majors because of the dangerous tenace in each major, and the spades barely beat out the hearts for second best.

So, as I was preparing this blog I spent some time rereading Winning Notrump Leads and, I believe, the results shown here are consistent with the book.  There are many factors in running the simulation and setting up the hands.  How weak/strong are you, the hand on opening lead?  What you have/don’t have leaves partner with the remaining assets for your side and affects what your strategy should be.  I could go on with many more hands (and so can you, if you acquire Lead Captain), but I decided to stop here.

Bottom line when considering your lead vs. 3NT when holding 4-3 in the majors…

  • Some of the differences (which lead is best) are minor
  • Tenaces are not only dangerous vs. suit contracts, but also vs. NT contracts
  • The 3 card major is not always best, but if the 3 card major is safe and the 4 card major is dangerous, always choose the 3 card major

 

 

2 Comments

RLPastorNovember 4th, 2017 at 1:07 am

In all the reading I’ve done about blind leads vs NT, the top factor is which defender holds the balance of strength. With only one entry card (AJ10xx) the aggressive lead is the Jd, but no doubt the 9h is more likely to produce 5 tricks. By the same logic the Kh from KQx seems better than leading a spade from 9xxx.
btw every time the auction goes 1c 1d 2nt 3nt and I lead my stiff club, declarer runs 6c and 3s when we could have cashed 5 hearts.

KJKNovember 28th, 2017 at 12:55 am

I have found lead captain to be very helpful in finding blindspots

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