JLOGIC, on 2011-August-07, 01:11, said:
In case it isn't clear yet, the reason to run the jack from dummy is to pick up KQTx on your right. It loses to stiff Q or stiff K on your left when compared to cashing the acew, but this is less likely.
These types of problems always intrigue me as to the psychology of the cards. If the situation is such that RHO knows what is going on, covering the Jack can be a net no-gain play. He might as well duck and lose the first trick, as the end is the same, all things being equal. For that matter, any card could randomly be played. Covering works as well as ducking, as well as sticking in the 10. Thus, in a sense, all four cards are equal.
With, however, Q10xxx or K10xxx, RHO is forced to play one of his three small cards. Hence, he has three equal options all involving ducking.
Thus, on a pure informational basis, one might argue that a pip from RHO will occur in one-fourth of all KQ10x scenarios. However, a pip will occur 100% of all K10xxx scenarios and Q10xxx scenarios. This, in theory, affects the odds tremendously.
Against that is that the person with KQ10x(x)(x) must actually play the small pip 100% of the time to ensure that the Q10xxx and K10xxx scenarios are not made more likely by the appearance of a small pip. Hence, RHO's play with KQ10x is restricted not by his own cards and the actual situation but by the hypothetical of a different deal and the need to protect that scenario.
Knowledge of what is going on, plus knowledge of what is occurring in hypotheticals, is critical to determining the likelihood of a particular card being played, therefore, and this knowledge or lack thereof determines odds. Knowledge can be affected, as well, by the position of the cards. For example, with A10 in hand and Qxx on Dummy, in a suit contract, Declarer has a line for 2 tricks in the suit without losers that is materially different than his options with A10 on Dummy and Qxx in hand. So also, J987x in Dummy opposite Ax in hand has different odds concerns than Ax in Dummy and J987x in hand, because of the different knowledge factor.
Flash cards rarely handle these aspects of the case. I have not myself seen any distinction in suit holdings depending on which holding is in Dummy and which concealed in hand, except situation-specific anecdotes.
"Gibberish in, gibberish out. A trial judge, three sets of lawyers, and now three appellate judges cannot agree on what this law means. And we ask police officers, prosecutors, defense lawyers, and citizens to enforce or abide by it? The legislature continues to write unreadable statutes. Gibberish should not be enforced as law."