Stepping Stone of Thunder

This hand is from the recent European Open Championship pairs championship. The hand needs to be viewed as a 3NT hand by West (sorry about that but the table closed down while I was still analysing it.) The play potentially involves two spectacular plays:

1. Days of Thunder: coined by Eric Rodwell it involves switching to an opponents long suit to hamper communications
2. Stepping-Stone Squeze: first analysed by Terence Reese in his classic "The Expert Game" and involves overcoming a blockage by throwing in a n opponent

North opens diamonds and West has a pretty obvious duck after the A and J - fair play to south if this is from AKJ. Now we see play one. If South can imagine a club blockage then switching to a spade creates a blockage in that suit.

This is not the end of the story if West can put South with 4+ clubs with the AH. He runs six spades and has now played 8 tricks. South must come down to either 4 clubs and the AH or 3 clubs and AQ hearts. In the latter scenario the clubs will run but in the former West can unblock the clubs and exit in hearts - thus using South as a stepping stone to the clubs.