To answer the questions from the two reviewers above, Japan released a DVD box set of all major works by Oguri, including Muddy River and His masterpiece Sting of death. I saw Muddy River in the early 80s and connected with this film deeply. Exceptional film and one of a handful of best movies about children. To the great list about child movie a reviewer mentioned above, I will add Ponette and Shoeshine t the list. Or even maybe Ivan's childhood. Ponette has probably the best child performance ever captured on the silver screen.
Oguri only made a handful of films in his career but undoubtedly he has left a strong impression on many cinephiles. I highly recommend that you guys check out his other films.