How to play this 3NT

[Fluffy]

[hv=d=n&v=e&n=sk7ha6dkqj853caq7&s=sa643hj1042d94c1086]133|200|Scoring: IMP

biding goes...

1♦-p-p-2♦*

3♦-p-3NT-p

p-p

 

2♦: alerted as 5-5+ in majors.[/hv]

 

The lead is the ♠10, wich has to be from ♠Q109.

 

Plan your play.

[inquiry]

There is the trivial case, when diamonds are 3-2. Win spade, knock out diamond ace, win 5D, 2S, 1H, 1C. That isn't very exciting.

 

There is the "pro" play of winning first spade in hand at trick one, and leading low dimaond towards dummy. This works when diamonds are 3-2 or WEST has stiff diamond ACE. Same nine tricks.

 

An interesting "world class" play of win first spade in hand with ACE, and duck a small heart to break their communication. This sets up an ENDPLAY on EAST when diamonds are 4-1 with ACE fourth behind the dummy. You can strip EAST's major cards and throw him in with last diamond for forced club return. win 2S, 1H, 4D, and 2C.

 

Which play to choose? Aha there is the rub. With 10 major cards, WEST is highly unlikley to have three diamonds (That would give EAST 7 clubs to KJ and he didn't bid or preempt). So West is 5-5-2-1, 5-5-1-2, or 5-5-0-3.. if 5-5-0-3, I think you are toast.

 

With ten major cards (vacant space principle), WEST is more likely to have a singleton diamond than to have one or two diamond.

 

However, since the one diamond could be the diamond ACE, the odds are better that he has either 2 or 3D, or the singleton diamond ACE. (singleton small = 38%, singleton ACE or any 2 or 3 D = 46%). Even it you remove form consideration the chance that WEST has Axx of diamonds (which was mathetmatically small), the odds still favor winning the ACE of spades and playing a diamond towards dummy (adjusted for 0 chance of three diamonds with WEST), by 40 to 43%.

 

So as cute as the win the spade ACE is and duck a heart, the math favors win the spade ace immediately, and play a small diamond. Now, 3% differene in the line, if table field suggest EAST has diamond ace.. maybe he hesitated before passing, maybe he flinched over 3D, you can choose the win the spade and duck a heart. But a second problem with win the first spade and duck a heart, you are always down now when WEST has the diamond ace, even if doubleton or tripleton, and you would have some explaining to do when you go back to compare scores...

 

Ben