Possible Clues:

• Japanese martial art that emphasizes not injuring the attacker
• Jujitsu kin
• Japanese martial art based on "The Art of Peace"
• Exceptional youngster facing old martial art
• Martial art created in the 1920s
• Adult 1 — child 0 in martial art
• Martial art founded by Morihei Ueshiba
• Art of self-defence gives splendid child a rounded character
• Martial art, akin to judo
• First class miner says nothing as a form of self-defence