Born in Gobo in Wakayama prefecture, Yukawa began his martial arts training in judo, studying under Tesshin Hoshi.
In 1931 he travelled to Tokyo to study at the Kodokan, but whilst in the city he encountered aikido's founder, Morihei Ueshiba, and was soundly defeated.
[2] He was strong enough to clap two sacks of rice together and bend iron nails with his hands.
[1][3] He died from stab wounds sustained during a fight with a soldier in Osaka.
This biographical article related to the Japanese martial art aikido is a stub.