Question 1

Where is Seimon Ishibashi?

Accepted Answer

Seimon Ishibashi is in Chiyoda, Tokyo, Japan. You can see its exact position from the map coordinates and the Street View link.

Question 2

Which scene of GATE does Seimon Ishibashi appear in?

Accepted Answer

Seimon Ishibashi appears in EP1 of GATE.

Question 3

Can I visit Seimon Ishibashi?

Accepted Answer

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

Question 4

Where was GATE filmed?

Accepted Answer

Anime and manga are not filmed the way live action is. Their backgrounds are painted from photographs of real locations, and Seimon Ishibashi is one of those real places (EP1).