Today, the Korbel's posted another deal that Dan played Monday night on BridgeBase online. They were in 7♣, eschewing a 4-4 spade fit that doesn't make the 7♠ grand slam because of a 4-1 spade split. He then discussed when to avoid 4-4 fits. You can read his post here.
Now it's my turn for a 4-4 fit story. Earlier today, a friend showed me a deal where an online player played a 4-4 fit in slam. What's that word? Oh yeah, serendipity.
Here are the two hands (low spot cards are approximate):
♠ 8 5
♦ Q J 9 8 6 5
♣ 10 6 5 2
♠ K Q 6
♥ A K 5
♦ A K 3
♣ A K J 3
It's always awkward to bid when one hand is so strong and the other so weak. The pair who played this deal landed in 6♣.
Notice that in 6NT, a club finesse is needed. You don't have the entries to lead up to spades twice. Even if you led to the ♠K and it holds, you can't be sure that West isn't ducking. If the finesse to the ♣J wins, you claim six diamonds, three clubs, two hearts and one spade. I make 6NT to be about a 50% proposition.
Playing 6♦ is better. You have entries to the North hand. Win, let's say, the heart lead, draw trumps ending in the North hand, and lead to the ♠K Q 6. If it wins, ruff a heart to North and lead another spade. If the ace is onside, you claim (six diamonds, two clubs, two hearts and two spades). If it is off, win any return, go to the North hand by ruffing a spade and take a club hook. If successful, that gives you six diamonds, two hearts, one spade and three clubs. I'm no math guy, but I make the combined chances around 75%.
The actual contract of 6♣ is the worst of the three. Because you are off an ace, you must bring in the club suit. If it splits 4-1 (or worse), you are down (unless there's a singleton ♣Q). If it splits 3-2, you still need the club finesse. I make it around 34%. (The math guys out there like Paul Gipson (The Beer Card) can probably tell you down to the one-hundredth of a percent, but you can see that the "magic" 4-4 fit is not where you want to be on this deal.
Daniel, your turn.