With Konishi Sensei's help, Funakoshi established a To-te practice club at Keio University (the first university karate club in Japan). Konishi Sensei, Funakoshi Sensei, and Ohtsuka Sensei were the principal instructors. Konishi Sensei continued to instruct a curriculum consisting of kendo, jujitsu, and western boxing at the Ryobu-Kan. Karate-jutsu was born when Funakoshi Sensei added karate to this mix. As yet, no names were applied to the emerging styles. Groups that practiced a pure form of jujitsu did not think highly of karate, and challenged Funakoshi Sensei. However, under Japanese budo, one does not initially challenge the Master of a particular school or style; a challenge is first issued to the senior student. If the challenger defeats the senior student, then he can challenge the Master. If the challenger defeats the Master, he can take the dojo sign as a trophy - a very embarrassing situation for the defeated dojo, and one never experienced by Ryobu-Kan. All challengers of karate were defeated by Konishi Sensei and Ohtsuka Sensei, as Funakoshi's senior students. After a challenge had been met, Funakoshi Sensei would explain karate-jutsu, and highlight the mental and spiritual benefits of the style. Many listeners understood and agreed to the point that they switched styles to study karate.

During this time, there was an ongoing philosophical debate among martial artists as to the definition of budo. Some believed budo required the death of the opponent; others, that budo meant supporting or educating the opponent in the proper ways. Funakoshi Sensei always taught budo as technique and education. Konishi Sensei especially believed "Bu bun ryo do", translated as "For karate to be perfect, it cannot be just technique, but also education." As technique disciplines the body, education should discipline the mind. Thus Konishi Sensei believed that Budo involves educating the opponent. Over time, three major changes occurred in Funakoshi's original karate teachings. First, because karate was introduced to the Japanese physical education program at the elementary school level, Funakoshi Sensei assigned Japanese names to replace the Okinawan names of the various kata, making karate easier to learn.