Question 1

Where is Toishi Castle Ruins?

Accepted Answer

Toishi Castle Ruins is in Ueda, Nagano Prefecture, Japan. You can see its exact position from the map coordinates and the Street View link.

Question 2

Which scene of Summer Wars does Toishi Castle Ruins appear in?

Accepted Answer

Toishi Castle Ruins is a real place that appears in Summer Wars.

Question 3

Can I visit Toishi Castle Ruins?

Accepted Answer

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

Question 4

Where was Summer Wars filmed?

Accepted Answer

Anime and manga are not filmed the way live action is. Their backgrounds are painted from photographs of real locations, and Toishi Castle Ruins is one of those real places.