Firefly viewing from May29-Jun13

Planning to add this to my upcoming trip to Tokyo from May29. I checked some areas and choosing between the Fussa firefly or Adachi firefly. Anyone here experienced the firefly viewing in these two places and which do you recommend?

If you have other places that you can recommend around Tokyo, much appreciated.

I have no experience in Tokyo, but fireflies are seen in the dark, so it really doesn't matter much where you'd see them. In other words, you may want to choose your spot depending on accessibility and what you can enjoy before dark, before the fireflies come out. Below is a list of Firefly spots. Mitaka would be the closest to central Tokyo, distance-wise.
https://www.gotokyo.org/en/see-and-do/nature/waterfront/seeing-firefli...