A more appropriate title for this movie might be "The Singing Swordsman" because of all the vocalizations. Chang Yi sings too.
The movie starts with a big battle scene using the castle wall outdoor set that will be around for many more Shaw Brothers movies to come. The castle defenders need help. The old master sends Chang Yi as Shen and with a secret weapon.
This was Chang Yi's second of three movies in his debut year at Shaw Brothers. He kept busy acting in this genre until about 1992 when he retired to Canada. This reviewer has searched for additional biographical information about him and has never found any. If I could interview him today I would ask first if he had any martial arts experience before acting. 1967 was before the time actors were expected to know martial arts. If it did happen, as with Lo Lieh who is also in this movie, it was a coincidence only. I suspect he had some experience. He did a front flip more than once and that skill does not come easily.
I rate the movie as slightly above average for the year and genre.