Posted 2011-July-19, 19:40
It seems to be the spade trick they got that made the difference between 90 and 120.
Here's my thinking:
At trick 2, I'd try a diamond to the King. If this wins, I take the club hook. If it loses, maybe they put you back in dummy by playing hearts and you can again play on clubs. If they return a spade or a diamond, you probably have to play on clubs from your hand.
You're in a similar situation after your ♦J wins. You don't want to play on diamonds any more right now, and you don't want to play spades because you're giving up a trick and are also about to establish the suit for them unless East has both honors. You could maybe lead a heart to the queen, but they could win ♥A and clear diamonds, and now you're still stuck in your hand unless you want to clear hearts for them as well, playing to ♥Q.
The ♦J was an understandable ploy to try to get to dummy's ♦K, but against good opposition it often won't work, and after you play it it's too dangerous to play on diamonds any more. Better to play up to the ♦K, which at least has a 50% shot of working, and, if not, forces them to play something back to you.