Bridge by Frank Stewart
When South opens 1NT, North's correct action is enigmatic. Maybe half of all players would raise to 3NT because of the 4-3-3-3 pattern and secondary values, including 10s and nines that will be useful at notrump.
The other half would bid two clubs, Stayman. Though North's pattern is flat, South's may not be, and a spade contract on a 4-4 fit may be best. To raise to 3NT would look silly if South held A Q 10 5, A 9 8, A Q 7 2, 5 2.
My view: North should bid his own hand instead of speculating about South's hand. I would bid 3NT.
In fact, 3NT was the better contract, and South made four spades only because East-West had a signaling error. When West led the king of clubs, East played the deuce. West treated that card as asking for a shift and led the deuce of diamonds next.
Dummy played low, and East had to play the queen. South took the ace, drew trumps, and forced out the ace of clubs. He won the club return, took the K-J of diamonds, and led the queen of hearts. East covered, so South lost one heart and made his game. If West had held the K-J of hearts, he would have been end-played when he took the king.
East might have signaled with the eight of clubs at Trick One since he didn't want a shift to anything, but West was more at fault. Dummy had no good source of tricks, so passive defense was indicated; no shift was imperative. West should have treated East's deuce of clubs as merely noncommittal.
If West correctly continues with the ace and a third club, South goes down.