How did Demon Slayer become the best-selling manga in Japan?
The engine was the anime, and the record shows the timing plainly. Koyoharu Gotouge's manga had run in Weekly Shonen Jump since February 2016 without topping the annual sales chart. The television anime premiered in April 2019, and Anime News Network's report on the 2019 Oricon chart records what followed: the manga entered the monthly series top 10 for the first time that April, at number 5, reached number 1 for the first time in August, and held it through October, with every collected volume gaining sales after the adaptation aired. New readers did not buy one volume. They bought the shelf.
The 2019 title was close, and the sources disagree in an instructive way. Oricon, surveying sales from November 19, 2018 to November 17, 2019, counted 12,057,628 copies for Demon Slayer against 10,134,232 for One Piece, making it the top selling manga series in Japan for the year and the first time in 12 years that One Piece had not topped Oricon's annual chart by series. Shueisha's own count for the same period put the order the other way round, 10.8 million for Demon Slayer against 12.7 million for One Piece. Both counts agree on the scale of the surge; they differ on the photo finish. In 2020 there was no photo finish to argue about.
Oricon's 2020 chart, surveying November 18, 2019 to November 22, 2020, counted 82,345,447 copies for Demon Slayer. Second place, Kingdom, sold 8,251,058. One Piece, with three volumes released in the period instead of its usual four, came third at 7,709,667. Demon Slayer also became the first franchise to top both Oricon's general book ranking and its manga ranking in the same year since Oricon began reporting the charts in April 2008. The circulation totals kept compounding after the manga itself had ended: 150 million copies in circulation by February 2021, a figure Anime News Network notes was about 43 times the circulation at the anime's April 2019 premiere, and about 220 million by July 2025, with 164 million in Japan and 56 million overseas.
The first volume, and the milestone art
The 2019 and 2020 charts measure the same behavior from two distances: an anime that sent new readers back to volume 1, and a backlist short enough, at under twenty volumes, for a new reader to buy all of it.