Akihabara is known for otaku culture but if you have already been there or feel too touristy, Nakano Broadway is an alternative. Located in a shopping mall next to the JR Nakano station, this seemingly ‘60s commercial building housing small retail stores that sell manga products cater to otaku people along with clothes vendors targeting local elderly people. It has a special old atmosphere that makes local Japanese people feel nostalgic.
I hope you'll bring some time with you, you can easily get lost in here. Everywhere new things to discover, new stores with a lot of great stuff.
Somehow I like Nakano Broadway much more compared to Akihabara, since it felt much nicer to walk around here.
Because you don't have to go outside, it's a good possibility to spend a day here when it's raining.
If you like anime and you can't find what you need here, then it doesn't exist. This place has damn near everything at a high price but better than places in Akihabara. Many movie figures, collectibles, cosplay, gotchapon. Too much to see this place will sap your money like a life steal ability from an RPG.