A traditional knockout as demonstrated by a kung flu grandmaster
Kung flu is a martial art that has been practised in Japan for many centuries, especially during the cold, sniffly winter months[1]. Proponents of Kung Flu follow a sacred text known as the Ah'Choo, This teaches them to turn the mighty power of the human sneeze against potential attackers.
Not only does this have an immediate effect in repelling and deterring opponents, but a few days later many of them wake up feeling a bit snotty and need to take the day off work.
[1] Includes spring and summer for hayfever sufferers
Other Martial Arts
Kung flu is just one of a number of Eastern martial arts that harness the power of the human body. Others include rudo (burps), pu-jitsu (bottom burps), and bogeydan ((aka snot-boxing ) in which contestants try to wipe the floor with their opponents.
Grandmasters gain the coveted green belt.