Gichin Funakoshi brought Shotokan Karate to Japan from Okinawa in 1922 as an alternative to Kodokan Judo. It emphasized kicking and punching, rather than the grappling, throwing, choking, and joint locking of Judo.
Funakoshi believed that Karate techniques were so powerful that they could not be practiced in a free-style situation (modern protective sparring equipment was not yet available). His motto was "one punch, one kill; one kick, one kill." He believed that free-sparring would dilute Karate techniques into light-contact or no-contact sparring, which was contrary to a true martial art. Funakoshi even modified Shotokan, which had emphasized short fighting stances, into long, powerful stances for the delivery of powerful techniques, believing the older, flexible fighting stances diminished the power of the single fatal technique.
One of Funakoshi's students, Masatoshi Nakayama also studied Judo. He used to return from Judo classes, where he had great fun with the Judo randori, and ask Funakoshi if a type of randori sparring could be developed for Karate. Funakoshi refused, believing it would degrade the power of Karate because it could not be practiced full-contact.
After Funakoshi died in the 1950's, Nakayama became head of Shotokan and began developing a competition style of sparring (protective sparring equipment was becoming more available). Shotokan developed a "light-contact" style in which action was stopped by a referee at the possible scoring of a point and points were awarded by colored flags raised by corner judges. This system developed the speed and reflexive response that Kano's randori had shown to be so important for realistic martial arts training. It became a very popular competition style in Karate, as well as for early forms of Taekwondo, and it remains popular today. The power of Karate techniques continued to be developed and demonstrated through breaking techniques.