Sensei (Kobe 06/02/1954) was born in a family of martial arts experts. At a young age he was taught a very traditional Japanese martial arts which came from the Banshu Region of Japan. This martial arts is called 門同流兵法 Mondo-ryu Heiho, which consists of the study of Jujutsu, Kenjutsu, etc. It was originally consigned to the group of the vanguard Samurai during the civil war era, as it was valued for its efficiency in battle. Now, he is the 15th Soke of Mondo-ryu Heiho. He also practiced Shitoryu Karate and Chinese martial arts.

When he was young he had some dangerous experiences, so he used his experience in traditional martial arts to defend himself.

Using his experiences in training and in real life, he developed his own system of self defence, a marriage between efficiency and simplicity, which he called Koroho (it is trademark); this word can be translated as "to continue to move forward with a pure soul". He has desire to improve martial art techniques by adapting them to reality, it is based on human instinct through the acquisition of simple techniques.

He had been in many foreign countries (South-east Asia, China and Europe) for the promotion of the international exchange, so this contemporary method of self-defense quickly came to the attention of the police forces in many different countries, many of whom asked Yokoyama Sensei to come and teach seminars in his style.​ Now he teaches:

- Mondoryu Heiho (family Jujutsu, Kenjutsu, Battodo)

- Armored Samurai Battle system (battle techniques of the 16th Century war era)

- Koroho (™) modern self defence system.