Image via Amazon Japan © Akita Publishing, Tamaki Kaigane, Kōji Yanagi
This year's 23rd issue of Akita Publishing 's Young Champion magazine announced on Tuesday that Tamaki Kaigane's manga adaptation of Kōji Yanagi 's Unbreakable ~Yaburezaru Monotachi~ (Unbreakable: The Undefeated) novel is entering its final arc and will move from the magazine to Akita Publishing 's YanChan Web platform next spring.
The story of the novel is set during the Peace Preservation Law of 1925, which targets those who believe in "Marxist" ideology. Proletarian writer Takiji Kobayashi chooses the harsh working conditions of a crab cannery ship as the subject of his next novel, which draws the attention of the special police task force charged with monitoring ideological threats. Two spies are sent to monitor his activities.
Kaigane launched the manga in Akita Publishing 's Young Champion magazine in August 2025. Akita Publishing shipped the first compiled book volume on June 19.
Kadokawa published the novel in 2024.
Yanagi published the original Joker Game novel in 2008. The novel won the Nihon Suiri Sakka Kyōkai-shō (Mystery Writers of Japan) award in 2009. Yū Irie directed a live-action adaptation of the novel, which premiered in Japan in January 2015. Yanagi followed up the original novel with three sequel novels — titled Double Joker , Paradise Lost , and Last Waltz — in 2009, 2012, and 2015, respectively. The series has more than 1.35 million copies in print.
Production I.G 's television anime adaptation of the Joker Game novel premiered in April 2016. Crunchyroll streamed the series as it aired in Japan, and Funimation streamed an English dub for the anime. Subaru Nitō launched the manga adaptation of the Joker Game anime in Mag Garden 's Comic Garden magazine in February 2016 and ended it in 2018. A stage play adaptation of the anime opened in 2017, with a second stage play in 2018.