Easter Eggs

The includes many Easter Eggs.

The Garden of Words film
There are some refers to Makoto Shinkai's previous movie, :

Yukari Yukino
Yukari Yukino, the female protagonist in that movie, made a cameo in as Itomori High School's Japanese literature teacher.

Leaves of Words café
The café that Taki and his classmates usually hang out is named "Leaves of Words", an alternative way to translate The Garden of Words to English.

Il giardino delle parole restaurant
The Italian restaurant that Taki worked at is named "Il giardino delle parole". This is the Italian translation of the title of the movie. Makoto Shinkai claimed that this easter egg wasn't added by him, but by one of the environment artists.

Takao Akizuki
Takao Akizuki, the male protagonist in that movie, made a very brief cameo near the end of the film. This easter egg was first revealed by Makoto Shinkai himself on January 3, 2018 as was broadcasted on TV Asahi for the first time.

Taki's English Notes
When Mitsuha met the younger Taki on the train, he was reading an English note that writes "I'm looking for my counterpart", fitting the situation.

Z-Kai advertisements
As Cross Road, Makoto Shinkai's animated commercial for the educational service Z-Kai, was the origin of Your Name, name of the service popped up randomly through the film.

Hyouka's real-life locations' presentation
On his journey for Mitsuha's town, Taki was looking at a map of Gifu. The presentation of attractions on the right of the map was taken from a real-life map for the anime Hyouka.