The Japanese market may not rival China or the US in size, but don't sleep on it. Plenty of indie games have found their biggest audiences right here in Japan. Backpack Battles is a great example: it topped the global wishlist charts in Japan even before launch, proof that Japanese players actively seek out great indie games.
I'm a native Japanese writer and a lifelong indie game fan. I got into localization because I wanted more great international indie games to be playable in Japanese, and I offer affordable rates to help make that happen for your game.
If you're wondering "would my game work in Japan?" or thinking about localization, feel free to DM me. Happy to talk it through!