Signature cuisine is at the centre of a police investigation after customers at revolving sushi restaurants posted video clips of themselves meddling with dishes

There are breaches of etiquette – drenching your rice in soy sauce, for one – and then there are heinous acts of “sushi terrorism”.

Japan’s signature cuisine is at the centre of a police investigation after customers at revolving sushi restaurants posted video clips of themselves interfering with food and playing pranks on other customers.