Complex sentence: Gadi is one of the few instructor in the world who recieved a special instructor certificate from Master Gozo Shioda, one that permits him to open a dojo in Japan and the rest of the world.
Split into simpler sentences: Gadi is one of the few instructors in the world who has received a special instructor's certificate from Master Gozo Shioda. It permits Gadi to open a dojo in Japan and anywhere else in the world.