Nowhere near as good as the first film. This exists primarily as its own justification, and with little reason to watch it.
Akira Kurosawa didn’t make many sequels, just two in fact. In both cases they were economically driven, where the studio he worked for wanted to cash in on a successful film he had made.
This film has very little of the spirit of its predecessor. It’s mainly a paint by numbers, filling in all the necessary elements for a decent story, without having any real purpose or point.
That’s not to say it’s totally unenjoyable. There are some decent moments, and some hilariously goofy characters. Still, like most sequels it never rises anywhere near the level of the original.
What is interesting is that it’s far more of a propaganda film. You could argue that there was a certain amount of inherent nationalism in the glorification of this period of Japanese history in the first one, but this is far more overt.
The film is pointedly drawing a comparison between Japan and America, coming down heavily on the side of traditional Japanese values.
Where the primary rival in the first film was, with his western clothing and attitude, a caricature, he was in comparison still a somewhat subdued take on imperialism.
Here we get American boxers, and Japanese businessmen pushing their fights. We get Japanese martial artists willing to debase themselves by fighting for entertainment and money.
We have rough American sailors beating up innocent Japanese taxi drivers. We have a contrast between the unprincipled Americans and the honorable Japanese.
It’s not at all subtle, even if I personally mostly agree with the take.