AK of hearts for me. This makes whenever the queen is doubleton, and half of the other 3-2 breaks - just under 50%.
An immediate low heart makes when the King of diamonds is onside and trumps are not 4-1 offside (unless they can get a first round diamond ruff).
Taking a diamond finesse planning to take the safety play caters for hearts 4-1 onside, and the diamond King onside. About one quarter of the Qxxx breaks. What you lose when they get an undeserved ruff is surely more than this.
But I suppose the lead matters too - did you bid diamonds during the auction? If not, Kxx in an unbid suit is an attractive lead, as is a singleton diamond. If diamonds were unbid, you might decide diamonds are more likely to be 2-2, and consequently the risk of trying the diamond finesse is not so great. Yet, on the other hand, a defender holding QT9x of trumps may choose not to lead from a King or a singleton anyway...
(edit) My last point is wrong I guess, if they don't lead a diamond because they have QT9x of trumps, and you take the diamond finesse assuming that playing on diamonds is safe, you have done everything you could to pick up QT9x, so that is not a problem.
This post has been edited by 655321: 2008-September-14, 18:22
That's impossible. No one can give more than one hundred percent. By definition that is the most anyone can give.