[mr1303]

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On the lead of the 8 of spades. You're in the good 7H. Now you need to make it.

Spoiler

If you try to draw trumps at any point, they break 3-1

[manudude03]

I'll play the dummy reversal. Win the ace, diamond ruff, ace of clubs, diamond ruff, queen of clubs, diamond ruff, KQ of hearts overtaking if I see the 9, otherwise cross to the king of spades to draw the last trump.

This requires both black suits to break no worse than 4-2 and trumps not 4-0, and there are some extra chances along the way. If the 9 of hearts appears before we have to decide whether to overtake the trump, we can survive a 5-1 spade break. Also, if the jack of clubs drops doubleton, we only need 2 diamond ruffs so we can just draw trumps then instead.

By the way, the tag is "spoiler" not "hidden"

[wank]

manudude03, on 2016-March-14, 21:54, said:

I'll play the dummy reversal. Win the ace, diamond ruff, ace of clubs, diamond ruff, queen of clubs, diamond ruff, KQ of hearts overtaking if I see the 9, otherwise cross to the king of spades to draw the last trump.

This requires both black suits to break no worse than 4-2 and trumps not 4-0, and there are some extra chances along the way. If the 9 of hearts appears before we have to decide whether to overtake the trump, we can survive a 5-1 spade break. Also, if the jack of clubs drops doubleton, we only need 2 diamond ruffs so we can just draw trumps then instead.

By the way, the tag is "spoiler" not "hidden"

i agree with the line but you should cash a top heart at some point to check for a 4-0 split

[mr1303]

Thanks both. Unfortunately the heart 9 didn't drop, and the lead was a stiff spade, so when I tried to cross back to the K of spades it got ruffed. Clubs were 3-3, so the suggested line (which I took) failed.

[johnu]

Just using some a priori percentages.

If trumps are 2-2, you can draw trump and claim.

Odds of a 4-2 or 3-3 split is 84% for each suit, or .84 x .84 = 71% for both suits to split favorably. Singleton 9 of trump gives the option of overtaking with trump ace to cash 8 if trumps are 3-1 instead of crossing in a black suit, assuming the opponents haven't already ruffed a black winner.

In clubs, you can make 4 tricks if 3-3, 4-2 with jack dropping, 5-1 with jack dropping, 5-1 with RHO having 5 to the jack, or 6-0 (as long you don't allow a ruff), 35.5% + 1/3 * 48.5% + 1/6 * 14.5% + 1/2 * 5/6 * 14.5% + 1.5% = 61%. If clubs don't break, you can make if spades are 3-3, or if RHO guards spades and clubs. Extra chances for spades breaking, (1 - .61) * (35.5%) = 14%. If neither black suit breaks, you can also make if RHO has J fourth in clubs, and the long spade on a show up squeeze. (1 - .61 - .14) * 1/2 * 1/2 * 2/3 * 48.5% = 2%. So ~ 61% + 14% + 2% = 77% chance of bringing in the black suits if trumps are 3-1.

So, win the ♠A, ruff a diamond, draw trumps. if 2-2, claim. If 3-1, cash a high club in dummy, ruff a diamond, cash spades ending in dummy, the last high club, play the last trump, and lead a club to hand.

[manudude03]

johnu, on 2016-March-15, 18:03, said:

Just using some a priori percentages.

If trumps are 2-2, you can draw trump and claim.

Odds of a 4-2 or 3-3 split is 84% for each suit, or .84 x .84 = 71% for both suits to split favorably. Singleton 9 of trump gives the option of overtaking with trump ace to cash 8 if trumps are 3-1 instead of crossing in a black suit, assuming the opponents haven't already ruffed a black winner.

I think you're forgetting to add the chances of trumps breaking 2-2 or stiff 9 (around 50% total of the remainder), though some of that also needs to be taken off since you effectively have to guess which black suit is more likely to break 5-1

edit: If those percentages were based on trumps not breaking, then ignore this.

[johnu]

manudude03, on 2016-March-15, 20:40, said:

I think you're forgetting to add the chances of trumps breaking 2-2 or stiff 9 (around 50% total of the remainder), though some of that also needs to be taken off since you effectively have to guess which black suit is more likely to break 5-1

edit: If those percentages were based on trumps not breaking, then ignore this.

I alluded to extra chances in the trump suit for the dummy reversal line, but I didn't bother doing additional calculations. If you add up the chances for 2-2 trumps or 3-1 trumps and an extra trick from the black suits, you are already better than the reversal line where you need at least a specific black suit breaking 3-3 or 4-2, and may need both of them to break favorably.

[Fluffy]

Spade lead should make it less likely that the suit breaks 5-1 against experts.

After spades 1-5, if hearts are 1-3 I think best is to play a club to the 9. With hearts 3-1 the partial dummy reversal looks way better.

So ♠A, ♦ ruff, ♥KQ (full dummy reversal if ♥9 falls), draw last trump and cash ♠K. Unless you plan to finesse ♣9 at this point, ruff a diamond, cash ♠Q and get to dummy with ♣A to play last trump.