Source: Asociacion Española de Bridge
Dealer South N/Vulnerable
* 1 of 5 keycards
** Ask for the queen trump
***I have it, and I dont have K
First Trick J, Q,K,A…how do you play? You have escaped a trump lead and now you are able to play a «cross-ruff: making 4 trumps from each hand plus (A, Ay K y A) for a total of 12 tricks.
However, yu must take a simple precaution before starting to ruff: immediately play A and K, to prevent a possible diamond discards from a defender, who will afterwards be able to ruff your diamond winners.
The correct line is: play the A, continue with A and K, play A and begun with the cross-ruff.