[pescetom]

Human partner had problems and GiB called in to substitute valiantly bid 6NT here.

Unfortunately the game plan was not perfect
Perhaps a "basic" robot, despite having paid to play the tournament?

[smerriman]

Subs are basic robots, I believe, but like last thread, would help a bit to know what you think the mistake was here Perhaps that GIB should take the club finesse first, so that the spade finesse is unnecessary if clubs are 3-3 with the queen onside? Though you're down regardless on this hand right, given there's no way you're dropping the spade queen?

Perhaps I'm missing an easy line to make.

[pescetom]

smerriman, on 2023-July-29, 16:15, said:

Subs are basic robots, I believe, but like last thread, would help a bit to know what you think the mistake was here Perhaps that GIB should take the club finesse first, so that the spade finesse is unnecessary if clubs are 3-3 with the queen onside? Though you're down regardless on this hand right, given there's no way you're dropping the spade queen?

Perhaps I'm missing an easy line to make.

Many humans made the slam (and nobody else in the tournament made this few tricks). If one or both of the minors behaves then surely we are home, with no need for three tricks in spades? Not only are spades less productive, but if they misbehave then we need both minors to behave, or so I mused as dummy.

In that light, trick 7 where it takes the spades finesse instead of the clubs finesse is a mistake unless I am missing something.

[smerriman]

Ignoring the resulting, that's agreeing with what I said, right? GIB should take the club finesse, but find out they're not 3-3, and then *go down* by finessing the spades as a last resort.

I'll look into why it didn't (which may well just be due to the fact it's a sub). but it definitely shouldn't be making the contract unless I missed something. (I'm guessing people made because East misdefended by holding onto the heart queen instead of the long club when the diamonds are run first, but GIB doesn't hope for misdefense).

[pescetom]

smerriman, on 2023-July-30, 13:59, said:

I'll look into why it didn't (which may well just be due to the fact it's a sub).

Thanks, I'm interested in whether or not a sub is basic even when I paid for the tournament. I do remember barmar a few years ago replying that even for my free tournaments a robot sub was advanced, but that turned out to be wrong and maybe it was BBO who pointed it out, cannot remember.

smerriman, on 2023-July-30, 13:59, said:

Ignoring the resulting, that's agreeing with what I said, right?

No, and not sure what your resulting point is either
I was just looking at the classification... at a certain point quantity is quality, if many made it then it was probably possible without defender error and on fairly obvious lines too. And if nobody scored so few tricks probably declarer screwed up.

smerriman, on 2023-July-30, 13:59, said:

GIB should take the club finesse, but find out they're not 3-3, and then *go down* by finessing the spades as a last resort.

Not what I though as an irate dummy... I thought the obvious line was to take ♣K to prepare the finesse and then tackle diamonds (longer and with only K a threat).
But even if we do take the club finesse immediately, it yields 4 tricks and now we can afford to lose ♦K with no need to finesse spades having 4 top tricks in the majors, unless I am missing something.

[smerriman]

By resulting I just mean it's possible that GIB went down without making a mistake no matter how other humans do. It may be unlikely, but you have to deliberately ignore the results to make sure you're analysing the situation in an unbiased way. In particular, I would have gone down myself with best defense, and the fact other people made it doesn't sway me - maybe there's another way to glean information that I'm not seeing, though it's more likely the line of play others took resulted in more opportunities for poor defense.

I think the key point you're missing is that whenever you decide to take the club finesse, it yields *3* tricks, not 4 tricks. You still need an extra trick in spades as well, and unless the defenders make things easier for you by gifting you an extra club trick (or giving up the spade position in some other way, e.g. on the lead), it seems you have to fall back on the losing spade finesse at the end.

But it still appears at first glance to be the wrong line by GIB (will investigate), since if you test clubs first and they break 3-3 with the queen onside, then it *does* yield 4 tricks, and then you don't need the spade finesse.

[smerriman]

Wow, this was actually quite a fascinating hand.. GIB might have actually gotten it right!

At trick 6, there are generally two lines.. one is to cash all the diamonds, then take the club finesse. If that holds, we still only have 11 tricks; for the 12th we need clubs to be 3-3, or the ♠K to be onside to make.

The second is to run the ten of spades like GIB did. This seems silly because even if it holds, we still need the club finesse.. or do we?

If it holds, the opponents are going to be under mighty pressure when we run our winners.. having to protect spades (either the Q if West doesn't cover, or the 9 if they do, which could even drop in the first 3 rounds), and also the queen of clubs, and potentially also the last heart.. I think with perfect discarding we may still have a guess in some cases, but at the table I suspect we'd know when West has had to bare the queen of clubs which they'll have to do on quite a number of hands.

So GIB's play actually looks like a better line to me.

[pescetom]

smerriman, on 2023-July-30, 16:28, said:

I think the key point you're missing is that whenever you decide to take the club finesse, it yields *3* tricks, not 4 tricks. You still need an extra trick in spades as well, and unless the defenders make things easier for you by gifting you an extra club trick (or giving up the spade position in some other way, e.g. on the lead), it seems you have to fall back on the losing spade finesse at the end.

I partly missed that, because in my "obvious human line" of diamonds then clubs finesse then if diamonds behave we only need 3 tricks from clubs. If the diamonds misbehave then yes we need a third spade in any case, although by then it might be evident that we can drop the Q.

smerriman, on 2023-July-30, 16:28, said:

But it still appears at first glance to be the wrong line by GIB (will investigate), since if you test clubs first and they break 3-3 with the queen onside, then it *does* yield 4 tricks, and then you don't need the spade finesse.

Yup, as I said.

As a sanity check, I analysed what happened in the tournament: of 23 in NT, 10 made 12 tricks, 5 made 11, 4 made 10, 3 made 9 and 1 (this GIB) made 8.
Of the 10 that made 12 tricks, 4 were gifted by a spades lead.
Of the 6 that made 12 tricks on a ♥J lead:
- 5 followed the "obvious human line", 4 taking the club finesse after running the remaining diamonds and 1 being gifted by a club return after losing to ♦K
- 1 (another GIB) laid down ♦A (!) and after losing to ♦K played 6♠ to ♠T and then pulled in the spades

[smerriman]

pescetom, on 2023-July-31, 10:02, said:

I partly missed that, because in my "obvious human line" of diamonds then clubs finesse then if diamonds behave we only need 3 tricks from clubs. If the diamonds misbehave then yes we need a third spade in any case, although by then it might be evident that we can drop the Q.

Ahh.. GIB had already lost the diamond finesse at the point it decided to forgo clubs so yes, that did turn out to be moot.

pescetom, on 2023-July-31, 10:02, said:

- 5 followed the "obvious human line", 4 taking the club finesse after running the remaining diamonds

But how did they make it after that? Did all of their opponents throw away the crucial club as I suspected, or did they really play for the drop in spades against the odds?

Come to think of it, maybe similar squeezes are in operation to the ones GIB went for if you don't cash the king of spades early, which I haven't looked at. That was in the first 2 tricks where GIB doesn't yet make a plan even if it were advanced. Having done so, I do like GIB's line though - still need to work out the exact odds.