[Limited 5,000 Copies Sold Out in 37 Minutes!] Live Sales Event for 'Can Furigana Improve Academic Ability?' by Masaru Matsumoto of the Ruby Foundation on YouTube Channel 'Only Yurindo Knows the World'

The General Incorporated Foundation Ruby Foundation aims to create a society where everyone can learn easily by promoting the use of ruby (furigana) in publications and digital content.

As part of its activities, the foundation announced that a live sales event for the new book 'Can Furigana Improve Academic Ability?' by founder Masaru Matsumoto, to be published by Poplar Publishing, was held on Tuesday, June 9, 2026. The event, titled '5,000 Copy Instant Sale of a New Book About Ruby ~Only Yurindo Knows the World #422~', saw the limited edition of 5,000 copies sell out in 37 minutes.

The live stream, during which the importance of ruby and the book were discussed, recorded a peak concurrent viewership of over 12,000. The comment section was filled with messages such as 'I understand the importance of ruby' and 'I hope ruby becomes more widespread,' creating a lively atmosphere.

Furthermore, all the award-winning works of the Ruby Full Taisho 2026, which were introduced alongside the book during the stream, also sold out, highlighting the growing interest in books with extensive ruby annotations.

Stream Date and Time: Tuesday, June 9, 2026, 19:00-20:30 Sales Time: 19:30-20:30 Number of Copies: Limited to 5,000 (Sold Out) YouTube Live URL: https://www.youtube.com/watch?v=VKr3jOox-rQ

Matsumoto also appeared in a video released on Tuesday, June 2, 2026, titled '[Trivia] The World of Books About Ruby,' where he discussed the history and role of ruby.

Video URL: https://www.youtube.com/watch?v=aqcWjzPuF2E Release Date: Tuesday, June 2, 2026 Cast: R.B. Bukkoro, Masaru Matsumoto (Founder, General Incorporated Foundation Ruby Foundation)

Book Information Title: 'Can Furigana Improve Academic Ability?' Author: Masaru Matsumoto Release Date: June 24, 2026 Price: 1,078 yen (including 10% tax)

About the General Incorporated Foundation Ruby Foundation Location: goodoffice Shimbashi, 2-5-2 Shimbashi, Minato-ku, Tokyo Established: May 24, 2023 Representative Director: Yutaka Ito URL: https://rubizaidan.jp/