This is sad news that you probably never knew about before. Bob Andersen was the British Olympic contender in 1952 for fencing and either instructed or did the stunts in the first few Star Wars movies, and the Lord of the Rings.
Even if you didn't know him, his swordfighting inspired a great many through the exposure on Star Wars. He inspired many new sword students. While Vader's costume is very much based on a samurai warrior in full yoroi armor with the addition of a black cape, the fighting style was not Japanese. It wasn't until the third movie (Return of the Jedi) did we see more Japanese style fighting. Then we had Ray Park playing Darth Maul in the newer Star Wars prequel that did an awesome job.