He was born in the town of Klang in Malaysia. Many Chinese gangs were active in the area, often carrying knives, machetes and spears. Koh was not an aggressive person and steered clear of them as much as possible.

He was fascinated by the Martial Arts and enjoyed watching the many Chinese forms practiced in the village backyards and temples. When a Budokan karate school opened up in his village Koh quickly joined. He trained 6 nights a week, and was rewarded with a double promotion, advancing from 8th to 6th Kyu.

A Keshin-Kan Instructor, Sensei Eiichi Yamakazi Kan then joined the club. One of Koh's fellow students was Clement Soo, who attained his Shodan and went on to become the permanent instructor at the dojo.

Shihan Koh remembers "I was lucky with Sensei Soo. He seemed to like me and every night when class was over he would teach me more Shoto Katas which he had learnt from the Philippine Instructors. Together we would train very hard, kicking a lot and practising our basics."

Koh's introduction to fighting was not too successful. "Tournaments in those days were very different, no mouth guards, no gloves or shin pads and no groin guards. The attitude was if you get punched, get up and punch them back. It was very hard and you really knew you'd been in a Karate Tournament. It was nothing to have as many as 3,000 spectators."

Shihan Koh earned his first Black Belt (Shodan) in 1969. In 1970 he won the Kata and Kumite at the Malaysian Championships. In 1972, he represented Malaysia at the World Karate Championships, and toured Australia with the World Karate Team. During this tour Shihan fell in love with Australia and decided to move here permanently.

He arrived in Australia in 1973 but experienced difficulty in setting up his style of Martial Art. Sensei Soo was aware of this and arranged for Koh to meet Soke Teruo Hayashi and suggested that he join Hayashi-Ha. Koh joined Hayashi in 1979 and was then faced with the task of learning the basics and approximately 20 Kata of the Shito Ryu style in a few short days. Soke Hayashi came to Sydney in 1981 and this was the first time that Koh had the opportunity to train directly under him. In 1990 Koh went to Osaka to train at the Honbu Dojo for 2 weeks, and successfully graded to 5th Dan.

In 2002 Koh returned to Japan to train with master Soke Hayashi.