Katsura Mansion

Katsura Mansion (桂マンション) is an apartment building in Wakaba, Shinjuku, Tokyo.

In Your Name
Lied very near to the Tachibana residence, this building's rooftop is the place where Taki Tachibana standed to watch the Comet Tiamat breaking and falling in 2013. It can also be seen briefly in the opening.

Real-life location
Located at block 1-21, Wakaba, Shinjuku, Tokyo, this 4-story building was built in June 1969. As its rooftop is on same height of the nearby hill street, it can be accessed from that street.

Its coordinate is 35°40'54.0"N 139°43'31.9"E

Trivia

 * Even though they are animated from the same rooftop of Katsura Mansion, the scene in the opening and the scene in the movie have the faraway skyscrapers (like the Tokyo Metropolitan Government Building and the NTT Docomo Yoyogi Building) in different angles. The scene in the movie is reproduced more authentically, while the opening scene is apparently captured from somewhere deviated 23° from the Tokyo Metropolitan Government Building. A likely candidate could be the Tomohisa Cross Comfort Tower.