Not sure why i don't know vul... but lets assume rho actually followed to the club (no mention). He surely has at least 6
♦ at imps, 2
♠ and already 1
♣, so at most 3
♥, and easily less. West club bid should have shown 5
♣ so when East followed we are thinking clubs are 5-1, giving EAST 2-4-6-1 or 2-3-7-1. You didn't say which club EAST played. If Ten or nine, the option of a deep finessee for 4
♣ tricks is present (should you decide to play for that), if the club was small, no such chance.
There are a number of reasonable squeeze chances. The
♣8 against WEST, the
♦4 against EAST (if east held 7
♦), and hearts against EAST or WEST). There is also an endplay chance. What did EAST throw on the 3rd round of trumps, i assume a diamond. Anyway, here is my line..
I duck a heart. I guess diamond back is good as any, I ruff and take
♣ hook. If East follows suit, his distribution is either 2-2-7-2, 2-1-7-3, 2-3-6-2. The solution here is easy. I ruff another diamond, and hook clubs again. If clubs are 3-3, i have 12 tricks (4C, 5S, 2H, 1D). If East has 2C only, then he has either 3 Hearts (2-3-6-2), and my 4th heart will be good, or he has 2 hearts (2-2-7-2) and West will be subjected to a
♣-
♥ squeeze when I used my last trump to ruff the last diamond. Position will be something like this...
Should EAST surprise us with 4
♣ (Kx with LHO), or RHO ducks from Kxx twice. the first time, he will have only one
♥ at most but we maynot be able to take advantage of this.
(3D) - double - (4cl (lead and support)) double
(pass) pass (4D) 5D
(pass) 5N (pass) 6D
(pass) 6S AP