One of the most surprising aspects of sumo for first-time watchers is the sheer violence of the sport.
Notions of cuddly pandas gently belly bouncing each other out of the ring get blown away when the first thunderclap of a harite (roundhouse head slap) echoes off the rafters of the arena.
It's also common for the jaws of those viewing a training session to drop open in shock when first seeing a wrestler receive kawaigari (tender loving care.)