Ep. 9: Building Nine explores the motivations behind the characters' shared passion for playing pranks on one another.
Aired on September 4, 2015

This episode focuses on the theme of pranks within the context of Building Nine. The narrative examines the reasons why the characters engage in these practical jokes and the dynamics involved in their interactions. The content centers on the enjoyment and intent behind these humorous acts, highlighting the playful nature of the group's relationships without delving into complex plot developments or external conflicts. The episode serves as a character-driven segment that emphasizes the lighthearted and mischievous aspects of their daily lives and social bonds.
Episodes
- Ep. 5 · Building Five features Satsuki in the anime clock narrative
- Ep. 6 · Building Six explores the fundamental necessity of learning multiplication tables in elementary school
- Ep. 7 · The Pool Opens at Building Seven as Siblings Enjoy the Water
- Ep. 8 · The Nakanos examine family history while questioning if all twins look identical.
- Ep. 9 · Building Nine explores the motivations behind the characters' shared passion for playing pranks on one another.
- Ep. 10 · Mutsuki Makes a Request in Building Ten
- Ep. 11 · Building Eleven: How Yayoi Nurses?!
- Ep. 12 · The connection between Haruki and his sisters is explored within Building Twelve