Chuya Koyama's Space Brothers Vol. 46 — the concluding installment of a manga serialised in Morning magazine since 2008 — reached No. 1 on the Billboard Japan Book Hot 100 chart released July 30, covering the July 20–26 tracking period. Billboard

Billboard Japan described the result as a "three-crown" finish, meaning the volume topped multiple book-related rankings simultaneously. The final volume also claimed No. 1 on Billboard Japan's Hot Manga chart for the same week, according to Billboard Japan's own report. On the Oricon weekly manga ranking — a separate sales tracker — Space Brothers Vol. 46 debuted at No. 1 with an estimated 138,012 copies sold, per Oricon.

The Book Hot 100, Billboard Japan's book chart, launched in autumn 2025 as the brand's first comprehensive ranking of book sales, extending Billboard's chart methodology beyond music. The chart tracks physical book sales across retailers and is published weekly at billboard-japan.com.

Behind Space Brothers on this week's Book Hot 100, The Apothecary Diaries (Kusuriya no Hitorigoto) Vol. 17 — a Square Enix manga adaptation — debuted at No. 2. Tsurumaikada's figure-skating manga Medalist Vol. 15 took No. 3. Both placements were confirmed in the same July 30 chart release. Billboard

The Book Hot 100 has seen several high-profile titles cycle through No. 1 in recent months. Eiichiro Oda's ONE PIECE Vol. 115 climbed from No. 2 to the top spot in July, with its digital edition slated for August 4, per Yahoo Entertainment. ONE and Yusuke Murata's One-Punch Man Vol. 37 rose from No. 7 to No. 1 on a July 23 chart, while Yasuhisa Hara's Kingdom Vol. 78 topped the ranking on January 29, according to Billboard.

On the music side of Billboard Japan's July 29 charts, idol group Nogizaka46's single "Zehi ni oyobazu" topped both the JAPAN Hot 100 and Top Singles Sales rankings. MECHATU-A's album On-Deck! led the Hot Albums chart, Mrs. GREEN APPLE headed the Artist 100, and composer Motoki Omori took the top spot on the Hot 100 Composers chart. Those music charts, unlike the Book Hot 100, have been a Billboard Japan staple since the brand's launch.

For Space Brothers, the No. 1 finish caps a run that began eighteen years ago. The series follows two brothers pursuing parallel dreams of becoming astronauts, and its final volume closing the chart at the top is a fitting send-off for a long-running serial — even if the numbers, not sentiment, are what put it there.