I have been trying to find info, that's why I started this topic. :)
So far, I haven't seen any Poles listed as interned by Japan, either in Japan itself or other parts of the empire, with the exception of those held at the Oyama Inn. I'd be thankful if anyone knew otherwise, though, and had some sources on the topic. All sources I've found so far (such as the ones on Manchukuo I mentioned above) seem to indicate that for most of the war Polish communities still existed in Japanese territory and ran their schools and whatnot as before, albeit with some wartime restrictions on things like rationing and freedom of travel.
In the book Między Warszawą A Tokio. Polsko-Japońska Współpraca Wywiadowcza 1904-1944
by Kuromiya Hiroaki and Andrzej Pepłoński and the book From Information to Intrigue. Studies in Secret Service Based on the Swedish Experience, 1939-1945
by C.G McKay, it seems that despite Poland's declaration of war, Polish and Japanese intelligence agents continued to cooperate in Europe, and that Japanese authorities actually protected Polish agents from falling in to German hands (e.g. Michał Rybikowski was allowed out to operate out of the Japanese intelligence station in Stockholm.) Some agents (like Rybikowski) were even issued with Manchukuo passes under aliases to disguise them from German authorities.
I don't know though how any of that cooperation in Europe translated over to Japanese treatment of Poles in Asia. That's what I'm trying to figure out, and again from what I've read so far I've been seeing mixed views (on the one hand, Poles being allowed to operate schools and community organisations in Manchukuo until 1944, and on the other hand Poles interned at an inn in Japan alongside neutral and Axis citizens).