Volume 17 of Square Enix's manga adaptation of The Apothecary Diaries (Kusuriya no Hitorigoto) reached No. 1 on the Billboard Japan Book Hot 100 chart released Aug. 6, climbing from the No. 2 spot it held the previous week. The chart tracked sales and engagement from July 20 to 26. Billboard

The Billboard Japan Book Hot 100 combines physical sales, e-books, library loans, subscription data, and social media activity — a broader measure than a pure sales tally. The Apothecary Diaries Vol. 17 gained points across brick-and-mortar stores, e-commerce, e-books, and social media in the tracking week. The comic version is credited to author Hinatsu Natsu, artist Nekokurage, and Shino Touko, and is published by Square Enix. Billboard Japan

Chuya Koyama's Space Brothers (Uchu Kyoudai) Vol. 46, the previous week's No. 1 and the final volume in the long-running series, dropped to No. 2. Tsurumaikada's Medalist Vol. 15 held steady at No. 3.

Two other titles made notable jumps into the top 10. Haruo Yuuki's novel Rakuen entered at No. 6, its first top 10 appearance, powered by a No. 1 ranking in social media and No. 11 in e-commerce. Nagano's Chiikawa: Nanka Chiisakute Kawaii Yatsu Vol. 8 leapt from No. 64 to No. 8, a climb that coincided with the Chiikawa anime film opening in Japanese cinemas on July 24. The film has since surpassed 4.4 billion yen at the box office, and its soundtrack placed No. 2 on the Billboard Japan Hot Albums chart.

Novelist Keigo Higashino died on July 23 at age 68. In the week following his death, four of his titles placed in the top 20 of the Book Hot 100. Majo to Sugoshita Nanokakan (Seven Days He Spent with the Laplace's Witch), whose paperback edition was released in June, was his highest-placing title at No. 7. Byakuyako (Journey Under the Midnight Sun) followed at No. 11, Yogisha X no Kenshin (The Devotion of Suspect X) at No. 12, and Hakucho to Komori (Guilt) Vol. 1 at No. 16.

Higashino's latest Galileo series novel, Eien no Kioku (Eternal Memory), was released Aug. 5 — one day before the chart published — and will be eligible for the next tracking period.

Rounding out the top 10 were Present at No. 4, Smoking Behind the Supermarket with You Vol. 9 at No. 5, In The Megachurch at No. 9, and HUNTER×HUNTER Vol. 39 at No. 10.

For readers unfamiliar with the Book Hot 100, the chart treats a book's reach the way music charts treat a song's — not just how many copies sold, but how often it was read, borrowed, and talked about. That blend is why a social-media surge for Rakuen or a box-office tailwind for Chiikawa can register alongside straight retail totals, and why Higashino's backlist moved back into view so quickly after his passing.