Ikka Matsuki is a Japanese manga artist and writer, known as the original creator of the manga series Nippon Sangoku. Matsuki made professional debut in 2020 with the work Bukuro Kicks. The ongoing series Nippon Sangoku, which began serialization in 2021, represents Matsuki's second major serialized work and first to receive an anime adaptation.

The manga Nippon Sangoku, written and illustrated by Matsuki, started serialization on Shogakukan's Ura Sunday website and MangaONE app on November 24, 2021. The series is published under the Ura Sunday Comics imprint. As of November 2024, six compiled tankōbon volumes have been released, with a seventh volume scheduled for April 2026. The series is published in France by Akata under the title Les Nations du Soleil Sanglant. Nippon Sangoku has received critical recognition, including nominations for the Next Manga Awards in 2022 and 2023, a ranking of 12th in the Kono Manga ga Sugoi! guidebook for male readers in 2023, and a nomination for the 16th Manga Taishō award where it placed fifth.

The story of Nippon Sangoku is set in a post-apocalyptic near-future Japan, where nuclear war, natural disasters, and governmental corruption have caused civilization to collapse. The nation has fractured into three warring states known as the Yamato, Seii, and Kanto factions, entering a new era called the Sangoku period. The protagonist, Aoteru Misumi, is a former agricultural officer who uses his vast knowledge and exceptional eloquence to pursue the reunification of Japan. The series is classified with the seinen demographic and incorporates genres including post-apocalyptic fiction, political drama, and alternate history. Matsuki has stated the work is largely inspired by the Three Kingdoms period of Chinese history, drawing from both the historical Records of the Three Kingdoms and the novel Romance of the Three Kingdoms.

An anime television adaptation of Nippon Sangoku, titled Nippon Sangoku The Three Nations of the Crimson Sun, was announced in January 2026. The series is directed by Kazuaki Terasawa and produced by Studio Kafka, with series composition by Teruko Utsumi, character design by Takahiko Abiru, and music by Kevin Penkin. The anime premiered globally on Prime Video on April 5, 2026, with new episodes released weekly in over 240 countries and territories. Commenting on the adaptation, Matsuki drew a distinction between the original manga and the anime, likening the manga to an official history and the anime to a romance that brings new life to the story through dynamic direction and voice acting.