Fuente: www.bawa.asn.au
They say that those who ignore history are condemned to repeat it. Players who sat West in the following two deals from a Mixed Pairs event some years ago may have had a great opportunity to learn from history:
Against 4
doubled, West led the spade jack to South’s ace, and a club was played at trick two.
The winning play is “second hand high” – go in with the king! This play forces South to win the club ace, and now there is no fast entry to enjoy the third round of clubs for a diamond discard. Indeed, if West does find the king play, South will likely duck it, and take the finesse on the second round – down two!
West actually followed with a low club, East won the queen and played a diamond, but declarer got it right, winning the diamond, taking a second club finesse and pitching the diamond loser on the club ace. Making four.
Interestingly, if East declares 4
and South happens to lead a club, then declarer must make the same “second hand high” play – the king to separate the defence from their second club winner. How symmetrically delightful.
Well, West can perhaps be excused for missing this play, but only a few deals later:
Against 3, West led the diamond queen, South let that win, won the second diamond, and played a club …
West must learn from history (and the bridge gods have been kind, making the key suit clubs again as an aide memoire) and go in with the queen.
But West actually played a low club – and the play was simple. The 10 forced the king, and declarer was able to subsequently draw trumps with a finesse, and repeat the club finesse to discard a spade loser on the long club. The defence didn’t have the communications to take three fast spade tricks.
Note that in both examples, going in with the club honour is relatively safe. On the first hand, South would obviously be finessing anyway if he owns the queen; and similarly on the second hand, one would expect South to finesse the opening bidder for the queen should he have started with 
Kxx.