Contestants on Hole in the Wall, a Japanese television show, stand on the edge of a pool of water as a moveable wall rushes towards them. To avoid being knocked in and soaked, they must contort their bodies to fit through variously shaped gaps cut into the wall – from basic “T”s and “L”s to comically positioned human silhouettes.

Such is the simple genius of Japan­ese TV. After clips of Hole in the Wall became viral hits on YouTube, Fremantle, the UK-based creator of Pop Idol, bought the rights to the format and sold them to broadcasters in 16 countries. Versions of the show will soon appear in the UK and the US.