Little Kid, on Jul 8 2008, 02:09 PM, said:
Ok, I tried to work it out and got the following:
Trumps first works if 2-2 or J single.
2-2 = 40%
3-1 with single Jack = 50%/ 4 = 12.5%
So I'm guessing taking trumps will work about 53% of the time?
Comparing spades to trumps:
If Spades 3-3, will make +1 compared to taking trumps?
So 36% of time this line gets one more trick than taking trumps?
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Yes. That 53% for the jack coming down is exactly the same as playing a 9-card fit missing the queen for no loser (and hence the 'eight ever, nine never' "rule" to play for the drop in this position).
Knowing a 3-3 break is 36% is another useful one.
Of course, sometimes both lines will work, but at the moment playing on trumps is nearly 20% better than playing on spades.
So, now we get to the difficult bit
Quote
If 4-2, then overruff diamonds or discard heart to get same or potentially better result than taking trumps?
So 49% time same or potentially better result?
The hard part is to work out how often we are making with spades 4-2. Let's split it into two:
i) LHO has the doubleton spade (about 25%). He will ruff the third spade. If he plays another heart, you will make every time you were making before, plus in addition if he ruffed from AJx or Jxx
If he switches to a club you are much worse off. You have to play another spade discarding the club loser (anything else is hopeless) and you now need him to have ruffed from an original holding Ax or from a singleton trump
Against good defenders you will be off most of the time.
ii) RHO has the doubleton spade (about 25%).
If he ruffs with the ace you discard a heart and will probably make.
If he ruffs with the jack you also discard a heart, and if he plays another heart you are very well off indeed. If he plays a club you are in much the same position - you win and play another spade, hoping him to have ruffed from an original holding of J or AJ doubleton.
If he ruffs low I think you are best to over-ruff and play a trump, making every time the trumps were originally 2-2, or he has ruffed from any 3-card holding.
This is very tricky to work out, but a completely random guess says you will make about half of the time. He won't always ruff with the right card.
This gives us an additional 15% (say) + the chance of a misdefence, on top of our 36% above.
I've come to the conclusion that the two lines are extremely close. And it certainly depends on whether the opponents know the heart count or not.
Not very helpful, but gives you good defence in the post mortem whichever line you took!