Question 1

Where is Hottarakashi Onsen?

Accepted Answer

Hottarakashi Onsen is in Yamanashi, Japan. You can see its exact position from the map coordinates and the Street View link.

Question 2

Which scene of Botan Kamiina Fully Blossoms When Drunk does Hottarakashi Onsen appear in?

Accepted Answer

Hottarakashi Onsen appears in ED9 of Botan Kamiina Fully Blossoms When Drunk.

Question 3

Can I visit Hottarakashi Onsen?

Accepted Answer

Yes. Hottarakashi Onsen is a real place you can visit. Check what it looks like on Street View before you go.

Question 4

Where was Botan Kamiina Fully Blossoms When Drunk filmed?

Accepted Answer

Anime and manga are not filmed the way live action is. Their backgrounds are painted from photographs of real locations, and Hottarakashi Onsen is one of those real places (ED9).