Question 1

Where is Oomien?

Accepted Answer

Oomien is in Fujisawa, Kanagawa Prefecture, Japan. You can see its exact position from the map coordinates and the Street View link.

Question 2

Which scene of Rascal Does Not Dream of Santa Claus does Oomien appear in?

Accepted Answer

Oomien appears in EP6 of Rascal Does Not Dream of Santa Claus.

Question 3

Can I visit Oomien?

Accepted Answer

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

Question 4

Where was Rascal Does Not Dream of Santa Claus filmed?

Accepted Answer

Anime and manga are not filmed the way live action is. Their backgrounds are painted from photographs of real locations, and Oomien is one of those real places (EP6).