Simplify the following text for a Grade 13 native English-speaking person.
Original: Yasuhiro Yamashita is an instructor or advisor for many organizations , including : TÅ kai University , the International Judo Federation , and the All Japan Judo Federation .
Simplified: Yasuhiro Yamashita is one of the most successful judo competitors of all time . He currently works as an instructor or advisor for numerous organizations , including Tokai University , the International Judo Federation , and the All Japan Judo Federation .