10 saunas in 2 cities
Eight of the ten Japanese saunas are located in Tokyo, the remaining two in Osaka. In a country with over a hundred million inhabitants, this is a narrow basis, and it says more about the data than about the scene.
Tokyo is thus practically synonymous with Japan for this category. Within the city, the offer is concentrated in a few districts; the map on this page shows this more clearly than any address list.
By the way, Japan is exactly the opposite when it comes to cruising addresses — each of the six cities has exactly one. There is no verified classification of the legal situation for Japan.
Gay Hotels leads Japan three. Together with the six cruising addresses, this results in a country that is represented in all three categories, but in none in significant numbers — which says more about this directory than about Japan.