From a Realbridge pairs event

The makeables table state that 6 can make against any lead,
and West duly reaches this contract. North led the K.

You win the heart king lead with the ace perforce and test the trumps with the ace, but South shows out!   Regard this as a double dummy problem now, i.e. you may look at all 4 hands, but you must assume best defense.

You will come across many hands like this where you need to take a timeout. Plan the play.
It is OK to take a full minute or two at the table to think at this stage!

Quiz: Make 12 tricks at double-dummy


Method 1: After South shows out in trumps, you resign yourself to losing a trump and since you have contracted for a small slam, you need to make the rest. At this stage we assume the K is with North (we can see that it is) and we proceed as follows -

tr 1:  K led taken with the ace
tr 2:  A but South shows out
tr 3:  Q advanced - covered by K and ace wins
tr 4:  back to J
tr 5:  ruff a spade
tr 6:  trump to king
tr 7:  the 4th spade!  If North ruffs higher than dummy, that will be his only trick;
       if he discards we ruff the spade, then get back to hand by ruffing a heart, we
       will then cash the trump lady and play on diamonds.  North can ruff when he wishes to.

Method 2: Same as above up to trick 5.

tr 6:  duck a club to North!
tr 7:  if N plays back a trump,           if N plays a heart, ruff      if N plays back a diamond,
       win and cash the last trump        and cash a trump              we win, ruff a heart and cash a trump
tr 9:  assuming a trump came back, we then cash the last trump and South gets squeezed.  
       He has to unguard his spade or the diamond, giving you your 12th trick.  The '
       last  5 cards are shown in the diagram that follows with South still to play.

TIP:   Take sufficient time to plan the play. Then put your plan into action.