This is a great film, written and directed by Yamada Yoji in 1970 --- about the same time as the first Tora-san films were coming out, and with many of the same actors. But unlike the Tora-san films, this is a serious film, not at all frivolous. I'm not sure if there is an English version available (either subtitled or dubbed).
Apart from its dramatic interest, the film is also of historical interest since it depicts the hard-driving 'go-go' era of Japanese economic growth, crowned by the World's Fair Expo in Osaka in 1970. You can see and feel rapid economic change and social dislocation everywhere in the film, and this in fact is the driving force behind the plot: a poor family of miners from Kyushu (the southernmost of the main islands of Japan) uproot themselves and make the long journey to what they hope is a better life in Hokkaido (the northernmost of the main islands of Japan). Their journey is beset with hardship and tragedy.
It's interesting that Yamada returned to this theme of the Kyushu-Hokkaido link, and the mining industry, in the later 1977 film Shiawase no Kiiroi Hankachi (The Yellow Handkerchiefs of Happiness).
You can look at 'Kazoku' as a film of social commentary, but, although Yamada depicts many of the social difficulties of the time, it's not clear what particular message, if any, he wants to impart about these. I don't think he is saying that economic growth and social change are bad, but he shows they plainly create a lot of upheaval and stress, and also a breakdown of fellow-feeling amongst men. As with most of his films, however, it ends on a positive note, where hope and human kindness eventually come to the fore.
