NickRW, on 2016-August-30, 06:37, said:
Perhaps an easier way to for an inexperienced player to think about this is:
1) How many clubs can South see? Yet West has bid to the 5 level in that suit. How many of them does West almost certainly have? How many does North have?
2) How many diamonds can South see? And how many has partner shown with the D2 lead? That leaves how many for West?
3) We've made a "weak with both majors" opening (implying at least 4 of each). Partner supported hearts to the 3 level (but not higher), implying how many? Leaving how many for West?
4) That leaves West with not many spades at all does it!?! How many?
5) Now think about being declarer and how the play is inevitably going to have to proceed depending on different trick 3 leads by South... Then you have the answer.
Perhaps the easiest way for the beginners to find solutions to such problems will be to think of it as a goal achievement such as,
1)We have already got two & require one more.Surely K
♣ if it can be protected being finessed two times.
2)How to do it-By shortening the club length in dummy.
3)How-By forcing West to ruff in dummy.
etc