Kōcha Agasawa is a Japanese manga artist and writer known for creating romantic comedy series that have been adapted into anime television productions. Agasawa began drawing manga as a self-published webtoon creator while working as an office worker, initially pursuing创作 in spare time before achieving professional serialization.

Agasawa is the sole author and illustrator of the manga series The Ramparts of Ice, which was first published as a webtoon before being serialized on Line Manga's digital service from January 2020 to April 2022. The series was later collected into fourteen tankōbon volumes by Shueisha under its Jump Comics imprint, released from July 2023 to February 2025. An anime television adaptation produced by Studio Kai is scheduled to premiere in April 2026, with Agasawa credited as the original creator. The series follows Koyuki Hikawa, a socially withdrawn student who struggles to interact with others, and Minato Amamiya, a boy who attempts to break through her emotional barriers.

Agasawa is also the creator of You and I Are Polar Opposites, a web manga serialized on Shueisha's Shōnen Jump+ platform from May 2022 to November 2024. The series was collected into eight tankōbon volumes, with English publication by Viz Media. The story centers on Miyu Suzuki, an outgoing high school girl, and Yusuke Tani, an introverted boy, exploring their developing relationship alongside their friends. An anime television adaptation produced by Lapin Track aired from January to March 2026, with a second season scheduled for July 2026. Agasawa is listed as the original creator for this adaptation as well.

The creation of You and I Are Polar Opposites originated as a strategic short work while Agasawa was facing the challenges of serializing The Ramparts of Ice. Lacking confidence in becoming a full-time manga artist, Agasawa devised a plan to create another short story to test abilities and generate interest for the ongoing series, which resulted in this second successful work. The one-shot for You and I Are Polar Opposites was first published in January 2021 before full serialization began.

Recurring elements in Agasawa's work include realistic character portrayals featuring ordinary protagonists rather than idealized heroes. The stories focus on characters who fear emotional vulnerability yet seek connection with others. You and I Are Polar Opposites notably departs from traditional slow-paced romance storytelling by having the female protagonist confess her feelings in the first chapter, with comedic elements incorporated to maintain emotional engagement. Agasawa's experience with webtoon serialization informs a deliberate pacing technique that places suspense points every four to five pages to accommodate modern reading habits.

Agasawa has received recognition through several industry awards. The Ramparts of Ice received a special prize at the Shueisha Shōjo Manga Grand Prix Powered by Line Manga Indies 2018 Summer before serialization. The series ranked first in the Comic Cmoa Annual Ranking josei manga category in 2022 and was nominated for the 69th Shogakukan Manga Award in 2023. You and I Are Polar Opposites placed second in the web category of the Next Manga Award in 2022, third in the Manga Taishō in 2023, and seventh in the Manga Taishō in 2024. Cumulative sales for You and I Are Polar Opposites have exceeded 1.45 million copies, while The Ramparts of Ice reached over 1.94 million copies in circulation as of August 2025.