Could be interpreted as a propagandistic cautionary tale about the pernicious influence of western culture (keep in mind when this film was made). In the film, westerners are portrayed as coarse, loud, and aggressive. They enjoy boxing, a spectator sport in which "they let men fight like dogs or roosters." Compare this to Sugata, who dresses traditionally, practices judo, and is comparatively calm and reserved.
Poor propaganda film that's as mediocre as a Kurosawa film can get with an extremely unsatisfying ending and some of the worst villains ever in a jidai-geki. Where the first and last fighting scenes of the first part were about as unconventional as could be, the opening and ending scenes of part II are just plain boring in their conventional long shot to medium shot cutting.
Fun to watch for symmetrical shots, nicely choreographed action and some zany characters that later show up in films like RAN (and KILL BILL.) However, this story has more topings than a deluxe pizza. Sanshiro almost floats through the rollercoaster of side stories, smiling at topics as they pass. Still in his experimental stage, Kurosawa did a lot with the opportunity he was given. Poor restoration by Criterion.