-cuz jon knows jiu jitsu.
Also name of a combination of western boxing and wrestling with self-defense "tricks", brought from Japan to Europe and the US around 1900 to 1920. In later years often practiced as a companion to judo or as "judo self-defense" until the modern systems were founded. This Jiu-Jitsu often was presented in film, e.g. in the Mr. Moto movies (starring Peter Lorre).
Self-defense arts called Jiu-Jitsu should not be mistaken with ancient Japanese Jujutsu styles, which are traditional, classical bujutsu (martial skills) of the Japanese warriors (samurai) and are in fact koryu (ancient budo). They have not much in common with the Jiu-Jitsu we know.
Unlike karate you dont have to bow to every fucking thing in the room.