Posted 2012-October-31, 21:11
When holding J9xx with the opps holding say A8xx in dummy, to your right, and KQ10x in hand (akin to the B1/B2 positions in OP) if declarer leads the K from hand, and partner follows low, you play the 9 to create the losing option, as OP suggested. However, declarer should always go to dummy first, in another suit, and lead from dummy. You play the 9, and partner will occasionally play the stiff 10.
I thought I'd post that as a counter to what is now a very well-known falsecard...indeed, if as declarer you hold KQ7x opposite dummy's A8xx, and have a knowledgable rho, always start, if possible, with low from dummy.
'one of the great markers of the advance of human kindness is the howls you will hear from the Men of God' Johann Hari