Winstonm, on 2021-October-20, 18:08, said:
We'll, you could play for Ax of spades onside or you could play for Kx of hearts offside. In both cases you would want to play on spades at trick two.
A combination of a below average play and one very below average play doesn't sound like it would be successful.
Assuming 3-2 splits in the majors for simplicity, a back of envelope calculation is:
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Ax onside - 50% doubleton onside and 40% chance ace is in doubleton = 20%
or
Kx of hearts in either hand - (100 - 20)% x 40% king is in doubleton = 32%
Total 20% + 32% = 52%
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Still assuming both majors are 3-2,
Taking immediate heart finesse
50% finesse is successful. Then
♥A and a heart ruff. Can't usually lose more than heart overruff and 2 trumps. If one defender has 2 hearts and 4 trumps, this limits defenders to an overruff and 2 trumps.
50% finesse loses. You only go down if a defender has 2 trumps and 2 hearts (without minor suit ruffs). Very roughly, this is about ~25%. So 50% x (100 - 25)% ~= 35%
Total = 50% + 35% = 85%.