Together with threefold European champion, the late Daniel Outelet, Clause became Abe's most skillful student excelling in both randori and judo kata.
After the departure of Ichiro Abe to Japan Clause was appointed by the Belgian Judo Federation to be in charge of the technical development of its members.
He held the position of national coach for two years, and was the liaison between the Belgian Judo Federation and ADEPS, i.e., the Ministry of the French Community of Belgium charged with the promotion of sport and physical education amongst the population of the French-speaking community, which organized the courses and issued the diploma's to the French-speaking candidate judo instructors and coaches.
Clause was in charge of the national technical trainings and judo kata clinics organized each once per month on the second and fourth Thursday, resp., in Elsene and Etterbeek.
In 1987 he was part of a group of four people (the others were Jean-Marie Falise, Théo Guldemont, and Pierre De Rouck) who became the first Belgian judoka to hold the rank of 7th dan.
[4][5] The Ligue Francophone de Judo in the 1970s for archival purposes did record a number of teaching videos showing Clause performing the gokyo, but none of the material has been released yet.