[bluecalm]

Quote

If you're playing MPs you'd lead the king pretty much all of the time. Imps is another story.

I think that form of scoring doesn't matter much. It's very difficult to find a hand where leading one thing is better at imps than at mp's and even if you find such hand the difference is usually very small.

[JLOGIC]

So, results: The K is better even with no possible entry? Thank you bluecalm and kgr.

[JLOGIC]

bluecalm, on 2011-June-12, 03:27, said:

Hmmm ?
97 QJT54 A65 765

7♠ - 120
Q♥ - 219
5♥ - 203
A♦ - 89
x♦ - 81
x♣ 107

Why it matters:
a)high h is better:
1)they have A9 to K8xx and not enough tricks on the side
2)K9x in dummy, Axx in partner's hand x2
3)They have 9x to AK8 or AK9 to xx x2
4)They haev AK97 to xxx in hearts but not enough tricks on the side

b)low h is better
1)partner has Kx and they have A9xx in one hand (Ax to K9xx) x6
2)K9 in partner's hand, they have Axxx

Admittedly it's very close.
If we substitute T with a 9 still Q wins slightly.
If we substitute T with an 8 then low is already better.

Guess I should have made the thread about this one.

The fact that it is this close double dummy leads me to believe that single dummy low is a big winner. For instance the major one is if dummy has Kx, in real life they will always play the king, double dummy they will duck to their 9.

Or if they have K9x opp Axx, they will often not play the 9 in real life, many people would duck for the purposes of blocking the suit rather than play for an underlead of QJT (this depends if they can read your spot card, and also might be rather circular). Likewise with AK8 or AK9, sometimes they will not be able to duck the first trick, or they might go up with an honor at trick 1 if they need an entry there rather thn attempt to run it to their 9.

Since double dummy greatly favors leading the honor in this situation, imo it backs up my judgement that leading low will work out better in real life.

[benlessard]

97 QJT54 A65 765

It would surprised me very much if a low H is a better lead than an H honnor IRL. I admit that double dummy favor an honor lead. I think the difference (16 cases) is greater than the case of declarer failing IRL but succeding double dummy.If the suit was a minor now it would be slightly better to lead low but not by that much (assuming staymand and opener bid a M) for example

can you run the sim a little bit longer or do you have the option to see in how many cases both lead succeed ? (that way we can calculate when leading low "blow" the defense and when leading high blow the defense)

[FrancesHinden]

bluecalm, on 2011-June-12, 10:59, said:

I have noticed that especially American players lead too aggressively. I even remember that Lawrence in one his books wrote that leading from xxx is usually terrible preferring active leads from honors. This is wrong and modern players lead more passively, especially ones from Europe.

Really? Obviously (as has previously been pointed out) Europe is not homogeneous... aggressive leads at IMPs are very common among good English players. MPs is of course a different game.

[FrancesHinden]

bluecalm, on 2011-June-12, 11:04, said:

I think polish leads are superior to standard and solve also those problems (as well as many others).
Those are:
A = AK
K = KQ
Q = QJ or AQJ
J = HJTx or JTx
T = Tx or HT9x
9 = T9+
2nd from xxx+ and Hxx, 4th from Hxxx+ and low from xx (including 9x but not Hx)

I am yet to see one hand where playing "strong ten" is superior to those but the ones when it helps declarer are plentiful (cause imo you really want to play J from HJTx and JTx)

If you really think that there are NO hands where strong 10s gain, then you aren't playing enough bridge. There are plenty of layouts where knowing at trick one that partner has made a strong lead is enormously helpful. There are layouts where it is enormously helpful to declarer, the point is whether you can work out from the auction which is which and lead accordingly.

[FrancesHinden]

JLOGIC, on 2011-June-12, 16:30, said:

So, results: The K is better even with no possible entry? Thank you bluecalm and kgr.

It wouldn't totally surprise me that even with no possible entry the K is better than a low one in the suit (although a different suit may be even better).

One huge advantage of the king lead is that declarer is often forced to duck and then you can switch successfully, a low one is very committal.
There is no mis-guessing upside from a low one either - one advantage of low from AKxx(x) (although it's going out of fashion) is when declarer gets a Q10 guess wrong (or low from KQ8xx declarer gets a J9 guess wrong).

- If the suit is 5332, partner having a doubleton, then the king is at least as good as a low one on every possible layout except Jxx in dummy and Ax with partner.
- If partner has 3 or 4, then the king is always at least as good as a low one
- If partner has a singleton, then it's the wrong suit to lead, but at least the king will usually allow you to switch; it costs when partner has singleton honour, but small singleton is 7:2 more likely
- If partner and dummy have doubletons and declarer has 4 then a low one gains when partner has precisely Ax; it loses when dummy has Jx; it loses a tempo when declarer has the AJ

[mfa1010]

FrancesHinden, on 2011-June-12, 06:03, said:

On a related subject, we've recently been discussing the merits of strong 10 leads. These can be a disaster when e.g. dummy has AKx and declarer Jxx; they work well in other situations, notably when dummy is short in the suit - partner leads a strong 10, dummy has singleton Queen, you know to put the king on from Kxxx, but if partner leads the 10 that could be from 1098x or from A109xx you don't know what to do.

There doesn't seem to be a problem covering dummy's Q from Kxxx regardsless, but I suppose you think of the situation where dummy has a small singleton. Then flying king would be bad opposite T9xx.

[JLOGIC]

FrancesHinden, on 2011-June-13, 13:47, said:

Really? Obviously (as has previously been pointed out) Europe is not homogeneous... aggressive leads at IMPs are very common among good English players. MPs is of course a different game.

Yes he is absolutely right imo, top americans lead too aggressively imo in many spots at imps. The Italians, Poles, Scandanavians all seem to lead more passive. Gavin and I were talking about this recently that one of the biggest changes in bridge at like the nationals is more passive leads, and we think this is largely from the amount of Europeans that come to nationals now plus vugraph. It is interesting to note that Meckstroth and Rodwell in particular have always seemed to lead more passive than their American counterparts. Of course, this is all just my opinion, maybe I just lead too passively, despite what this thread might suggest!

[han]

The day after the hand with Justin came up I had the following:

xx J1087xx Kxx xx

RHO opened 1NT, LHO bid 2C Stayman, RHO bid 2S, LHO bid 2N (not promising a 4-card major) and RHO bid 3NT. Should I lead low or an honor?

[bluecalm]

Quote

Obviously (as has previously been pointed out) Europe is not homogeneous... aggressive leads at IMPs are very common among good English players. MPs is of course a different game.

This is only my observation from vugraph. As I saw more vugraph hands than probably anybody else and analyzed play of many top pairs extensively (and made some stats about first lead success for example) it's more than just casual observation but still only an observation of someone who never played at top level (or close to it).
When I talk about "European players" I mean elite players which by definition is very narrow group of the best players who win a lot in international competition and are frequent guests on vugraph.

[bluecalm]

Quote

If you really think that there are NO hands where strong 10s gain, then you aren't playing enough bridge. There are plenty of layouts where knowing at trick one that partner has made a strong lead is enormously helpful. There are layouts where it is enormously helpful to declarer, the point is whether you can work out from the auction which is which and lead accordingly.

I am not claiming there are no layout like that obviously. I just think it matters so rarely that it's not worth it.
I also don't believe there are many (or any) people out there who could make agreements like: "if bidding suggest we profit more from strong T then we use it and if bidding suggest declarer profits more we don't)" and making more gains from it than losing due to misunderstanding.

Quote

xx J1087xx Kxx xx

RHO opened 1NT, LHO bid 2C Stayman, RHO bid 2S, LHO bid 2N (not promising a 4-card major) and RHO bid 3NT. Should I lead low or an honor?

J♥ - 369
8♥ - 357
4♥ - 356

On 1000 hands sample (dd simulation) assuming opener has 4spades and max 3 hearts and responder doesn'thave 4 spades and is in 8-9hcp range.

I went quickly through some hands and one funny example of when leading low was right is Ax in dummy and 9xx in hand. One example of J being right was KQx in dummy and 9x in hand which points that low heart may be better than dd simul suggests.
Also if there is K9 in dummy and Qxx in hand declarer will often play the K (same with Q9 opposite Axx) - those cases seem to be quite common and could tip the balance toward leading low.
Interesting stuff, unfortunately I am busy with some other things right now so I had to postpone writing my own simulator which would make easy to just list every hand when it mattered which would be helpful to improve our intuition about this stuff.

[JLOGIC]

han, on 2011-June-14, 01:52, said:

The day after the hand with Justin came up I had the following:

xx J1087xx Kxx xx

RHO opened 1NT, LHO bid 2C Stayman, RHO bid 2S, LHO bid 2N (not promising a 4-card major) and RHO bid 3NT. Should I lead low or an honor?

I would lead low. Again I feel like bluecalms simulation confirms this, on top of the KQx 9x variation, there's also Q9 in dummy and Ax(x) in hand type variations or Qx A9(x).

[bluecalm]

With 5 card suit instead of 6carder it's even closer dd (J♥ - 362, low - 356). It would be really nice to have a feature which counts various ♥ configurations so we could improve on dd analysis but for now the only way is to just go manually through the hands and count them

Also matchpoint analysis could be better than imps analysis, because then even on smaller sample the difference will be more apparent. Unfortunately those takes forever and I can't run too many cases.
I made 1000 hand simul with 5 carder (xx JT87x Kxx xxx) and the results were:

J♥ - 768
7♥ - 725
4♥ - 723

I went through first 250 hands, and there were following situations:
-Q9x - xx, would declarer play 9 or Q ? (probably Q more often) x2
-Qx to A9x - probably again declarer would play the Q x2
-Kx to Q9x; usually declarer plays a K from it

So in first 250 hands there were 5 cases where leading low is no worse but dd simuls shows it's worse. This of course suffesrs from sample size issues but it shows it's very very close.

Funny case which I encountered when going through the hands where the one where low is better with this configuration:
AQ96 vs K2 where leading low upsets declarer's communication

[whereagles]

This simulation scheme is nice. Bluecam might re-write the standard leads book based on them

[han]

The scoring was Patton btw, but I was too afraid to mention that. Dummy had Qx and declarer A9x. Of course declarer played the queen and my diamond king stopped the diamonds so it made for an easy set. The lead of the jack or ten gives declarer a chance.

[benlessard]

for a sim of 1000 hands

south lead with
76,JT87xx,KJx,76


East has 16-17 pts bal with exactly 4S but not 4H. West has 8 pts not 4S not 5H


i get

9 where leading J or low H make a difference double dummy.

JT wins
Q9 vs Ax (eliminated because IRL he would play the Q)
K2 vs Q93 (eliminated)
KQx vs 93 (elim)
qx VS a92 (elim)
KQ6 vs 93 (elim)
Q9 vs Ax (elim)



AQ92 vs k6 (north has axxx,x,qxxx,AJT9 )

9xxx VS AQ

Q93 vs A62 (eliminated because north has obvious lead directing X of 2clubs)

so for the 1st 1000 its 0-2 in favor of leading low.

The next 1000 set ill remove the J of D.

[benlessard]

for a sim of another 1000 hands

south lead with
76,JT87xx,Kxx,76


East has 16-17 pts bal with exactly 4S but not 4H. West has 8 pts not 4S not 5H

i get

6 cases where leading high or low H make a difference double dummy.

JT wins

Q6---A9
AQ62---K95 (this is only legitimate case where leading high is best.)
Q9---K65
Q5---A96
Q5---A9
Q9---A5

LOW win
none


so far for 2000 its 1-2 in favor of leading low.

[benlessard]

leaading High win

Q5---A9 (elim)
q6---A9 (elim)
A9x---KQx (elim -- leading low give declarer an important 2nd entry but IRL the contact go down 100%)

Q9---Kx (leading low give declarer a very important entry so its eliminated)
Q9---A62 elim

leading low win
9xxx--AK (eliminated since declarer can only make double dummy crazy endplay)

1-2

now for the last 1000

edited

[Cascade]

bluecalm, on 2011-June-14, 06:02, said:

J♥ - 369
8♥ - 357
4♥ - 356

These numbers surprise me.

Am I misinterpreting them. It seems that almost every time the card led was crucial since they add up to only slightly more than 1000.