[cencio]

how to play this 3nt?


note: remember that the breakdown 3 and 2 occurs 68% of the time, that the impasse is worth 50%, that the breakdown 3 3 occurs 36% and then impasse + division 3 3 = 68%

I post the better solution when i will know it

[Cyberyeti]

Pairs or teams ?

Note that playing spades is good odds, any 3-3, any 10/10x/K10 will also do.

Also playing a spade at trick 2 can win if W makes an error and does the smartass holdup.

I think spade to the J at trick 2 may be best odds in practice although not in theory.

If it loses, you need W to hold K10 or E to hold 10x or them to be 3-3.

If it wins, you need clubs 3-2 or diamonds 3-2 and if those fail you need the ♠K to be right.

Broadly speaking spade finesse right plus 3-3 with it wrong is the equivalent 68% of diamonds 3-2. I think the extra chances when spades are 4-2 or 5-1 pretty much cancel (K10 W or 10x/10 with E for playing spades, K10/K/Kx with E for A♦ and duck the second round if W follows).

This leaves 2 things to net off, if diamonds are W1E4 you will see they are not breaking when playing diamonds so take K and take the spade finesse and get some of the advantages of the spade play, if it wins you need clubs 3-2 or something good to happen in the spade suit. You net this off against the chance that W ducks the K♠ assuming you will repeat the finesse.

[gszes]

I will go with the immediate spade finesse. I make whenever the K is onside OR the suit breaks 33 OR the T is singleton or doubleton AND (I do not now if this is IMPS OR MP) if the spade K is onside 3rd I have ten tricks on top and am playing for overtricks.
trick 2 spade finesse (assuming it wins)
trick 3 dia to A
trick 4 another spade finesse (if it wins hand is over and we are playing for overtricks)
trick 5 spade A to see if 33

if spades are 33
trick 6 cash the 4th spade who knows maybe some unfortunate soul with Txx in clubs OR diamonds (dummy does look entryless u must admit, AND our play to the dia A makes it strongly appear we started with xx(x) or Kx at most, will pitch 1 and we can run 4 clubs or diamonds
trick 7 if a dia was pitched we have to try and see if the dia run since we will then have 13 tricks (5d 4s 2c 2h)
if a club was pitched we have to decide to safely duck a club OR now try to cash the club suit ducking a club will squeeze either player if they are holding a club AND a dia stop but will fail if the minor suit guard are split. Cashing the AK
will get us 4 clubs if they are now 22 and still get us a 3rd club if they are 32 (I go for the AK play because if we can score 4 clubs we might convince a player (pitching at trick 10) to come down to 2h and 1d vs 2d and 1h and if so we
get 13 trick 4s 4c 2h 3d.

if spades are not 33
trick 6 duck a club
there is still the off chance one player might be stuck with 4c and 3d (maybe even the 4th spade) and will be squeezed

IF i do not care to think of all the above (tired bored or whatever) i will simply duck a dia at trick 2 and if dia fail to break 32 I will hope for the K(x) spades onside to make my contract.

[nige1]

cencio, on 2018-March-21, 03:29, said:

Win ♥A, finesse ♠Q.
- If the finesse loses to LHO's ♠K, then you need ♠ 3-3 or ♠T doubleton/singleton.
- - If the ♠ finesse wins, then cash ♣A.
- - - If both follow, then cash ♣K.
- - - - If both follow, then concede a ♣.
- - - - - If ♣ don't break, then cash ♦A and lead another ♦.
- - - - - -If LHO follows, then duck a ♦.
- - - - - - - If ♦ don't break, then fall back on a 2nd ♠ finesse.

[steve2005]

Spade finesse trick 2 if works or someone holds up you can play on clubs. If clubs then don't split you can go for spades again.

[PhilG007]

cencio, on 2018-March-21, 03:29, said:

how to play this 3nt?


note: remember that the breakdown 3 and 2 occurs 68% of the time, that the impasse is worth 50%, that the breakdown 3 3 occurs 36% and then impasse + division 3 3 = 68%

I post the better solution when i will know it

The simplest solution is win A♥ then play a low diamond and duck it. If the suit breaks 3-2(a 65% chance) you are home making 4 diamonds,2 clubs two hearts and

one spade. Taking the spade finesse immediately is risky. If it loses,West will return a second heart knocking out your last stopper before you have set up the diamonds

[kbrat]

I would go for diamonds splitting 3-2, ducking the first round, even if i'm left with only one chance for a spade finesse. Too many "if's" when going for 3 spade tricks.

[awm]

The spade finesse is around 48/64 (32 king onside plus 10 3-3 king off plus 6 KT off, Tx on, stiff ten).

Diamonds breaking is only about 40/64. So you need to make a lot of times when they don’t break to catch up. Ducking a diamond pretty much gives up here — much better to start ace and a diamond planning to win king if LHO shows out the second round. This means 13/64 diamonds don’t break but you find out before losing a trick. You need to make a little more than half these for playing on diamonds to beat the spade finesse. What are your chances here?

Start with spade finesse. You can pick up the following:

Spades 3-3 (20/64)
Spade Kx or K onside (6/64)
Spade Tx or T stiff either hand (11/64)

You can also combine chances with clubs 3-2 if the spade king is onside fourth or fifth (10/64 times around 2/3).

Seems like this combined line is the winner?

[0deary]

Duck diamond, and if they split 1-4 then end play East with Diamond exit provided South takes one successful Spade finesse and also stripped off top Clubs: playing for 5242 shape?

[miamijd]

It's close, but it looks like playing Ace and a small diamond is marginally better than playing on spades first.

Diamonds first:
If you want to play on diamonds, A and low is MUCH better than an immediate duck, because without losing a trick, you'll not only find out if either opponent has all 5 diamonds (low first only finds out if East is void) BUT ALSO if West has a stiff. If one of these happens, you switch horses. If 5/0, play a diamond to the King and hook the spade. If it wins, you play on clubs for the ninth trick (and if that doesn't work, hope for Kx doub with East); if it loses, you hope for stiff or doub ten or 3-3 spades.

On the second diamond, if West shows out, you again switch horses by winning the King and hooking the spades. If it wins, play AKc and if that doesn't work, hope for a doub Ks (doub ten won't help you; you can't lose another trick, as the opps will have a spade tow diamonds and two clubs). If it loses, hope for stiff or doub ten of spades.

If East shows out, then you have to win the heart, play to the Kd, hook the spade and hope for Kx of spades with East.

This line works out to about:

.68 + (.14)[(.5)(.68) + (.5)(.08)] + (.14)(.08) + (.04){(.5)(.68) + (.5)(.54)] or about 77%.

Spades first:
No West is going to duck the Q or J of spades here. Get that out of your mind
If the spade hook wins, you are pretty much home, as a previous poster indicated (AKc; if clubs don't split, A and duck a diamond; if D don't split, then second spade hook). Since I think the second spade hook here is 100%, I will take the full 50% if the spade K is right.

If the spade hook loses, you have to hope that someone has a singleton or doubleton ten of spades OR that spades are 3-3. A doub ten is about 16%; a stiff ten is about 2%. These aren't quite right, because you have to take into account the fact that West must have the Ks and so can't have the stiff ten of spades, but they are close enough.

So this line looks like:

.5 + (.5)(.36) + (.32)(.18) = approximately 74%. Not quite as good.

[Stephen Tu]

I don't think miamijd's calculations are quite correct. By my careful calculation, relying on spades alone (not touching diamonds) is 77.05% to succeed.

Trying diamonds first:
Let's say diamonds are 1-4. There are a couple plausible lines here:
1. Finesse, just play on spades ignore clubs. This works 63.71% of these cases.
2. Finesse once, if win try clubs then back to spades. This looks strictly better than 1, because if LHO has 4+ clubs, you still get to bang down ace and pick up stuff like doubleton T offside, since RHO won't have entry to get to LHO's club winners, so you can still score 3 spades. So this basically gives you extra chances if KTxx onside, if LHO is 2713 and won't overcall 2nt with 3h. This gets you an extra maybe 2.94%. So 66.65%. If spades are 5-1, I think LHO would have bid something with 8311 distribution.

If diamonds are 0-5, odds are slightly different, I make it about 61.55 for spades to behave, but I think LHO would bid if 2803 so no real extra club chances.

So overall about
67.83 + 66.65*.1413 + 61.55*.0196 = 78.45%.
Plus some fraction when LHO has 5 diamonds, that's harder to calculate since some of those would lead diamond instead of heart? So it looks like a couple percent better to play on diamonds first.

[miamijd]

Stephen Tu, on 2018-March-22, 18:24, said:

I don't think miamijd's calculations are quite correct. By my careful calculation, relying on spades alone (not touching diamonds) is 77.05% to succeed.

Trying diamonds first:
Let's say diamonds are 1-4. There are a couple plausible lines here:
1. Finesse, just play on spades ignore clubs. This works 63.71% of these cases.
2. Finesse once, if win try clubs then back to spades. This looks strictly better than 1, because if LHO has 4+ clubs, you still get to bang down ace and pick up stuff like doubleton T offside, since RHO won't have entry to get to LHO's club winners, so you can still score 3 spades. So this basically gives you extra chances if KTxx onside, if LHO is 2713 and won't overcall 2nt with 3h. This gets you an extra maybe 2.94%. So 66.65%. If spades are 5-1, I think LHO would have bid something with 8311 distribution.

If diamonds are 0-5, odds are slightly different, I make it about 61.55 for spades to behave, but I think LHO would bid if 2803 so no real extra club chances.

So overall about
67.83 + 66.65*.1413 + 61.55*.0196 = 78.45%.
Plus some fraction when LHO has 5 diamonds, that's harder to calculate since some of those would lead diamond instead of heart? So it looks like a couple percent better to play on diamonds first.

I trust your calculations a lot more than mine, Stephen, although I think you neglected to split the diamond line in two:

1. You find out about the bad break before you lose a diamond trick (5-0 or West is short). Then your line 2 above is right.
2. You don't find out about the bad split without losing a diamond trick (Ad, small d, duck in dummy, East shows out). Now you can't try line 2 and in fact are reduced to playing East for Kx of spades.

It's probably more likely that West is short in diamonds than East (West rates to be slightly longer in H), but I think the possibility that East is short in diamonds (you don't find out until some of your options have been eliminated) reduces the diamond pline %age slightly.

Actually the main point of my post was that on the diamond line, ducking the first diamond, as everyone up to the point of my first post suggested, is very wrong.

Best,
Mike

[Stephen Tu]

miamijd, on 2018-March-22, 19:45, said:

I trust your calculations a lot more than mine, Stephen, although I think you neglected to split the diamond line in two:

1. You find out about the bad break before you lose a diamond trick (5-0 or West is short). Then your line 2 above is right.
2. You don't find out about the bad split without losing a diamond trick (Ad, small d, duck in dummy, East shows out). Now you can't try line 2 and in fact are reduced to playing East for Kx of spades.

It's probably more likely that West is short in diamonds than East (West rates to be slightly longer in H), but I think the possibility that East is short in diamonds (you don't find out until some of your options have been eliminated) reduces the diamond pline %age slightly.

Actually the main point of my post was that on the diamond line, ducking the first diamond, as everyone up to the point of my first post suggested, is very wrong.

Adam mentioned the diamond ace, diamond up ducking only if LHO follows in a post preceding yours.

You are right I forgot the chances with LHO having 4 diamonds, RHO having Kx of spades, this gives an extra fraction of a percent (maybe 0.3%) to the diamond line. It's pretty small because 4540 is going to be super rare since that gives RHO all the missing clubs, 4441 not too common either, giving RHO SKx/KT. Assuming heart lead is from length, anyway, discounting 4342 type shapes very heavily. Basically I think you are almost always screwed if diamonds split 4-1 rather than 1-4 when you are trying to duck a diamond if LHO follows.

[0deary]

Super analysis above, reflecting how N/S actually got into 3N if East has just 2H W would have a very odd quiet holding 8 carder, and similarly after their 3H S might well X not try 3N on just Kx, so at best W has 6 hearts and east ample communications to apparently wreck us. So I wonder if we need to squeeze West out of some of hearts and only so if west also has busy cards too...so action through the diamonds....?