Koji worked as in-house accountant from 1979 to 1991 for Kubota, Ltd. (a Japanese giant company in the field of manufacturing agricultural machines and iron pipes) due to his speciality of corporate accounting at Hitotsubashi University.

His unique experience is that he lived and worked in East Germany from 1984 to 1988 just before the fall of the Berlin Wall when Kubota was a contractor for building a large foundry in Leipzig, East Germany. He can do with a daily conversation in German.

After leaving Kubota, Ltd., he drastically changed his job and worked for Fukami Patent Office as trademark paralegal and attorney for 25 years from 1991 to 2015.

At the age of sixty, he founded his own IP Law Firm on Jan. 1st 2016, which will be a base camp for his life time attorney and artist.

From 2014, he also provides IP law lectures for students in Tamagawa University in Tokyo once a week.​