Matchpoint line check, look at single dummy first, double dummy in spoiler:
2H-4H auction
A
AK8
J874
AT962
972
QJT532
5
KQ8
Lead is K spades
Pull trump and claim 6 is easy, but there is play to make all 13 tricks. Win spade lead, club to hand, ruff spade high, heart to hand, ruff spade high, club to hand to pull trump and then pitch the diamond on long club. This fails (makes 5 instead of 6) when trumps are 4-0 or clubs are 4-1. Is it correct to try for 13 here?