South was declarer in 4♠ after a weak NT and transfer auction. I led ♦6, won by declarer with the ace. Partner got on lead with the ♠K and led a club to my ace.
I decided the diamond suit looked dangerous and was almost certainly about to be used for discarding losers, so I switched to a heart, won by partner, and that was the end of the defence.
I needed to play a diamond for partner to ruff, one down.
If partner had cashed her heart ace before putting me in, maybe I would have twigged it, but unless the same position comes up again, I will never know if I'd have found it.
AL78 "South was declarer in 4♠ after a weak NT and transfer auction. I led ♦6, won by declarer with the ace. Partner got on lead with the ♠K and led a club to my ace.I decided the diamond suit looked dangerous and was almost certainly about to be used for discarding losers, so I switched to a heart, won by partner, and that was the end of the defence.I needed to play a diamond for partner to ruff, one down.If partner had cashed her heart ace before putting me in, maybe I would have twigged it, but unless the same position comes up again, I will never know if I'd have found it."
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Yes, East can help West to find the ♦ continuation, by cashing ♥A
As JohnU points out, if West encourages ♥ then ♥K is as good as ♣A.
Hugh Kelsey wrote a book about such deals, where you can help partner defend.