What non-Japanese people were available to be extras in a Japanese movie in 1963?

Just watched Kurosawa’s High and Low.

There’s a nightclub scene with some white guys and some black guys. They’re just extras, in the background, not involved at all in the plot, none of them have any lines. Although none of them are in uniform, I kinda assumed they were meant to be U.S. Military (all the women were Japanese, I think, just men who were white and black).

Who, non-Japanese, would have been in Japan in 1963 available to be extras in a movie? Is it possible the movie extras actually were U.S. Military? Would their situation have allowed time to be extras on a movie set?

Who was living in Tokyo in 1963 that would not have been of Japanese ancestry? Were there industries that hired from abroad? Were there whole communities of non-Japanese at this time?

I’m not asking incredulously. It was not a shock to me to see people who were not Japanese. It just got me wondering how easy it would have been to find extras for a movie if you wanted some non-Japanese people in the crowd.

They might have been off duty soldiers from the Yokosuka Naval Base nearby.

Actual for real off duty soldiers is what I was thinking. Just wasn’t sure what kind of off duty availability those guys had.

My (slightly educated) WAG is also that it’s off duty military folks. That would be the logical “to go” place for casting agents looking for foreign extras.

However a lot of westerners doing other work - consulting/teaching/research/study etc. have been encouraged to submit a headshot to casting agents due to the paucity of available people - if they need a westerner in the background and you even remotely meet the requirements you could make some good money for a day’s work.