nice to meet youWelcome to mavicpilots.com, "neighbour" ! ;-) (also living in Setagaya-ku and owner of a Mavic Air2 here ^^)
Well, sadly we have in deed tons of restrictions around. Best is you check this post which has several infos on the topic. Basically, as you noticed, it's restricted everywhere "officially" and where it is not, it is also "inofficially" (local restrictions, private, etc). Like you, i searched a lot, and thought about tama river shores, green areas like golf spots etc too, but found out it's also prohibited by the ward, just not reported yet on the official map from MLIT. Your best bet to train is sadly to join a drone school (hangar training, sucks but well...) or move to a dedicated place like i did, which is sadly not a good fit for a regular training solution. Only other alternative would be to find some relatively remote area and fly there very early in the morning (before 5-6AM ?) when no old wanabe "policeman assistant" is roaming around (many cases of delation in Japan). But like me, Setagaya-ku : dame desu... Everything remote is out of reach without car/train. Feel free to contact me for further infos or even to meet and plan a fly together maybe. =)

I'm curious if you might think this area would be ok to fly in? It's suspiciously left off the no-fly areas of the maps along the outskirts of the area. I ride my bike here quite frequently and there are always lots of people fishing along the lower road. It's located where the Toyosu BBQ place is and would give some nice shots of Tokyo over the water.
thx
