Black Belt (2007), known as Kuro-obi (黒帯) in Japan, is a Japanese martial arts drama film directed by Shunichi Nagasaki. It focuses mainly on the martial art of Karate. It is notable for excluding the usual exaggerations of the genre. The lead roles were played by karate experts, and no special effects were used.[2][3] In the film, three students of an elderly karate master decides among themselves on who deserves their master’s black belt. … The events take place in 1932 in Japanese-occupied Manchuria, in which the corrupt leaders of the Japanese army are trying to take over all the Karate dojos (a kind of training hall) for their own benefit.

https://en.wikipedia.org/wiki/Black_Belt_(2007_film)

The link above has the Japanese dub and English subtitles, but has an annoying watermark. If you want something else, here are your choices:

• https://www.youtube.com/playlist?list=PLuxami9vLt9F9_kycFa1XPTTQcMZ5qoem - English subtitles, no watermark, but broken into several smaller videos.
• https://www.youtube.com/watch?v=A5UGm6GLKsg - Spanish subtitles
• https://www.youtube.com/watch?v=ejxzbsL7VlQ - Japanese dub, no subtitles
• https://www.youtube.com/watch?v=7RwGX0A7N50 - another Japanese dub, no subtitles
• https://www.youtube.com/watch?v=uNmNGqza6UU - portuguese dub? / vietnamese subtitles (click on “CC”)
• https://www.youtube.com/watch?v=50v9bPkUWvw - portuguese dub but potato quality (114p)
• If you want to watch Invidious versions of any of these links, just replace the string “www.youtube.com” with “invidious.fdn.fr”

Fun fact: the actors who play the three students are each an expert in a different karate tradition: Shotokan, Goju-Ryu, and Kyokushin.