[kgsmith]

Hi all

I am new here, so I hope I get the format right. With no opposition bidding, I played the hand in 6♦ by East on the lead of the ♠8. I would like to know what the best line is. I tried to cash the top two clubs, intending to ruff a third club with the ♦10 and a fourth with the small diamond if necessary. The obvious alternative is to cash three top diamonds and hope the club finesse is right if they don't break. Which of these, if either, is the percentage line?

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For what it is worth, my line failed immediately when clubs were 5-1 and the ♣K was ruffed.

Thanks
Kevin

[johnu]

Even if you don't think the bidding, type of scoring, vulnerability, or cards played don't matter (and they may not on any particular hand), please include them as there may be clues which may affect the analysis.

[nige1]

kgsmith, on 2015-March-10, 14:33, said:

I am new here, so I hope I get the format right. With no opposition bidding, I played the hand in 6♦ by East on the lead of the ♠8. I would like to know what the best line is. I tried to cash the top two clubs, intending to ruff a third club with the ♦10 and a fourth with the small diamond if necessary. The obvious alternative is to cash three top diamonds and hope the club finesse is right if they don't break. Which of these, if either, is the percentage line?
For what it is worth, my line failed immediately when clubs were 5-1 and the ♣K was ruffed.

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Welcome kgsmith. I like your line

[WesleyC]

Welcome to the forums kgsmith!

For what its worth I disagree with johnu - although it's usually nice to include the auction/scoring it clearly isn't relevant on a hand like this (assuming the opponents just passed throughout).

Crunching the numbers on the two lines:

Plan A (Taking a club ruff with the ♦T)

Wins automatically if clubs are very favourable (♣Q, ♣Qx or 3/3) and the diamonds are 4/2.

= 54% (clubs very favourable) * 84% (diamonds 4/2)
= 45.4%

If clubs are xx/Qxxx with RHO holding the length, you lose only if LHO has a doubleton diamond not including the ♦3 (e.g can ruff both rounds of diamonds and still leave RHO with a trump trick).

= 16% (♣xx/Qxxx) * 72% (favourable diamonds)
= 11.6%

If clubs are Qxxx/xx with LHO holding the length, you lose to the ♦J offside, and also to a doubleton diamond offside.

= 16% (♣Qxxx/xx) * 28% (favourable diamonds)
= 4.5%

This line also risks an enemy ruff very occasionally (just an estimate).
= -1.5%

Adding these together gives the overall chance of success of ruffing a club with the ♦T at roughly 60%.

Plan B (Playing three round of diamonds, then if 4/2 try the club finesse)

Wins when:

Diamonds are 3/3

= 35%

And when Diamonds are 4/2 and the clubs are favourable (♣Q,♣Qx,♣Qxx,♣Qxxx onside)

= 48%*43%
= 21%

The overall chance of success starting with 3 top diamonds is roughly 56%.

So Nige's instinct was right - your line looks slightly better than the alternative (but not by much)!

[kgsmith]

Thanks WesleyC.
Much appreciated!

[helene_t]

Your line also has the advatage that North can make the mistake of not ruffing the third club. Maybe impossible against good defenders but who knows. If you cash diamonds and take the club finese, the defenders can't make mistakes.

[helene_t]

At match points your line has a further advantage. The field may be in six notrump in which case you need a line that works while 6nt is down.

OK, some declarers may get a heart lead which could complicate things.