This is deal 1 from Jean‐Marc Roudinesco’s Play Bridge With Me.

♠AKQ32
♥K8
♦AQ
♣AKQ4
♠J98
♥A72
♦K42
♣8765

Contract: 7NT
Lead: ♥ 10

Hint 1 What options are there for how to play the spade suit?
Hint 2 Could you guarantee making if you could see all the hands?
Hint 3 Can you test something before deciding which way to play the spades?
Solution (slick)
  1. Win with the ♥ K in dummy.
  2. Discovery play: test two rounds of clubs to find which defender guards them.
  3. Play the spades so as to fail when the defender guarding clubs also guards spades:
    • If West guards clubs, start with ♠ A.
    • If East guards clubs, start with ♠ J.
  4. Now you can either pick up the spades directly with a marked finesse or execute a simple squeeze on the defender guarding both clubs and spades.
Note that this contract is therefore cold on any layout and any lead, although the claim at trick 1 is somewhat convoluted.
Solution (lowbrow) This solution wasn’t given by Roudinesco and doesn’t involve any difficult plays but merely counting. It’s probably easier to find for a non‐expert but harder for the expert (for whom squeezes are second nature).
  1. Win with the ♥ K in dummy.
  2. Cash 2 top clubs. If everyone follows, you’re done.
  3. Else cash remaining top hearts and diamonds (i.e. unblock diamonds, cross to ♥ A and cash ♦ K), pitching ♣ 4.
  4. At this point, you will always know at least one defender who cannot have all 5 spades (check this for yourself), hence play the spades accordingly. Note that a top club is still available in the North hand to reach the 4th and 5th spades.