But two handscrolls displayed as a coda to the show remind us that Dong's classification has its limitations.

WSJ: Paths Easy and Daunting | Ming Masterpieces | Artful Recluse | Lacma | Asia Society | By Lee Lawrence

They have taken their lead from US regulators, who gave it a PG-13 classification.

BBC: Parents warned of Spider-Man violence

This step moves us closer to meeting the recent Jobs Council recommendation to enable regulations to be searched by North American Industry Classification System (NAICS) codes, (NAICS is a standard used by Federal agencies in classifying industry).

WHITEHOUSE: Regulations.gov: Remaking Public Participation