The bidding: South, with 17 high card points and no five-card suit, opens one notrump. A hand with a five-card suit usually plays a point higher or more. North transfers to spades and jumps to four diamonds showing a singleton diamond. After transferring, a rebid of three diamonds would show a second suit of likely five cards. Any jump is a splinter showing a singleton or void.
South has no wasted values in diamonds and cuebids the ace of hearts. Had South been caught with values in diamonds, he would just jump to game showing no slam interest. North cuebids his ace of clubs and South cuebids his king of hearts skipping diamonds because he does not have the ace of diamonds. North places the contract in six spades.
When partner opens 1NT, one should think slam with a seven-card suit and 12 points or 9 points and a singleton. How does North know partner has the ace and king of spades and not the ace and king of diamonds? North knows this because with Ace and king of diamonds, South would not be interested in slam and would not offer any cuebids.
The Lead: Just because the opponents splinter is not a reason to lead the suit. If you take an ace without having the king, the opponents will get a pitch on their king. Here a diamond lead is fine because West has both the ace and king. He can play the ace and then look at dummy to see what suit to switch to. A club looks like a reasonable switch.
If West had values in hearts, a heart switch would be better, but a heart lead just finesses partner out of anything he has. A club lead will not give anything away.
The play: Declarer draws trump and claims.
The result: 6 = for +980
Notes: -Cuebidding sequences to get to slam are superior to asking for aces with a worthless doubleton. Blackwood or Keycard Blackwood are not useful when one is asking with a void or a worthless doubleton. The cuebidding sequence told North that slam was very likely.
-All the bridge columns may be viewed at http://watsongallery.ca.