Criterion’s UHD is an improvement over Toho, it has better compression, grain, and doesn’t use the noise reduction and slight sharpening present on JPN.

Video comparison: https://slow.pics/c/mTDmYlq5

Mono audio-wise, USA UHD takes the lead here, with the JPN UHD being similar, but with more high roll-off and boosted bass, and all other sources sounding far more muffled.

Unfortunately, unlike Yojimbo, NOR disc/BFI Player WEB-DL (which again share the same mastering) don’t offer a higher quality untouched track.

3.0 is close between USA and JPN UHDs, Criterion’s UHD has a bit tighter bass and was preferred. Older Criterion disc is noticably worse.
USA UHD comes in a 5.1 container with 3 empty channels, stripped to 3.0 and encoded with DTS MAS (768k core).

Audio comparison:Spectrogram https://slow.pics/c/2JOk8JD7

Spectrum analyzer:
https://slow.pics/c/0C44qjSv

Samples: https://mega.nz/folder/TJJSnQhC#ujHSTRb66Q4sX5ZHbUBihg

Criterion commentary sourced from the old disc, as UHD is lossy and filtered. Added captions for it from Criterion Channel.

Included both Criterion and BFI translations. Added missing periods to the BFI track. A brief comparison can be found here (https://web.archive.org/web/20230607121420/http%3A%2F%2Fkurosawamovies.com%2Fcomparisons.htm) of Yojimbo, but this film is the same