A number roughly accurate (their source link is dead now, as the article isn't from this year)
However, my estimate number of japanese escorts is pure speculation based on the country population. It can be far less due to the fact that I should only include girls 18+ to maybe 45 (for a very very large spectrum). So, even if I refer to the number of 100,000 women, 20 000 is only 20%. 80% of the women are from other countries. In maths, 20% is clearly not a lot compared to 80%.
It doesn't matter how far less is compared to general population, that article says there's basically no prostitution performed by Japanese women except those who occasionally need some money to buy something they need.
This sounded rather false
So the question was: is that true? How many Japanese women escort? How many among the 100,000 to 150,000 professional prostitutes it claims are in Japan are actually Japanese?
It didn't matter it was an old study we're working with proportions and estimates , they wouldn't change much over the years unless some cultural revolution occurs
The answer is: a lot , 20% is the minimum and it's certainly less than the remaining 80% it's a fifth meaning that still at least one every five prostitutes you see is Japanese and this is the very least number , the lower estimate based on how many Japanese pornstars are there and that only a few of them end up escorting , we're still on thousands grounds .
Let's now try to imagine some more accurate proportions even staying on the estimates field, there would be no reason to think that those foreigner women would enter into prostitution but not JAV porn, it would be absurd for at least two reasons porn is still seen as "better" than prostitution, there is some transition between porn and mainstream movie making ,all over the world it's not unusual to have some pornstars on set or even to have former pornstars becoming mainstream actresses or the other way around , so in a way being a porn performer is still less dishonorable than just being a prostitute . Other than that an escort who was formerly a pornstar can charge more , she has fans and is "famous" and people dig famous people, would love to say I fucked (name at will) , it was glorious.
So a foreign prostitute has an interest in trying to become a pornstar first .
All this to say there's an interesting thread here on Akiba-Online this one:
https://www.akiba-online.com/threads/mixed-blooded-jav-actress.1240554/
It focuses on Mixed and Foreign performers in JAV , if you sum up all the namese put in there you may notice how few they are , maybe less than 100 and this even taking into consideration actresses who were active some 15 years ago,even doubling the number of those mentioned it's still incredibly low
If those are the proportions there's no reason to think it'll be enormously different when it come to prostitution, so the actual number of Japanese women escorting can't be so disproportionately low as I estimated before, the real proportion could very easily be the opposite 80% Japanese and 20% something else.
I want to still lay low, I'd say not every girl is suitable to be a pornstar ,a girl could be not good enough or even be downright ugly , or too unreliable being an addicted or a drunk , and even though it would apply to the Japanese women too , I can't ignore what the Wiki said , that many foreign women in Japan escort , so I'd lower my estimate doubling their number , we will still have around 60% and 50% if I want to stay generously low
Secondary evidence would be the escorts I found with my first search , they were all Japanese.