Sho Kosugi's sons play Ken Tani's children.
Kosugi's voice is not dubbed, as it was in "Enter the Ninja, "Revenge of the Ninja", and Ninja III: the Domination"
Not released theatrically in most countries. However in the UK, Australia and Europe this film did quite well on VHS rental about two years after it debuted after Van Damme started to become a major action movie star in the early 1990s.
Although Van Damme is second billed, he in actuality is only in 15% of the movie. The movie is 100 minutes long, and a count of all his scenes totals approximately 15 minutes.