OTOBANK Co., Ltd. (Headquarters: Bunkyo-ku, Tokyo; President and CEO: Yuya Kubota), which operates audiobook.jp, Japan's largest audiobook distribution service, is now offering the lullaby music "Sounds That Make Babies Sleep Instantly," created by the General Incorporated Association Chiba Institute of Auditory Science (Chiba City) and which has received a significant response, for free within the audiobook.jp app. By utilizing this app, users can enjoy background playback and ad-free listening, further supporting the environment for putting babies to sleep. ■ Background of Distribution "Sounds That Make Babies Sleep Instantly," produced by the General Incorporated Association Chiba Institute of Auditory Science (Chiba City), has garnered a huge response, with cumulative downloads exceeding 385,000 in approximately one month since its release, and over 15,000 comments, emails, and phone inquiries received. While the lullaby music was originally scheduled to be available on the Chiba Institute of Auditory Science website only until the end of June 2026, its free distribution on audiobook.jp has been decided through the cooperation of the Chiba Institute of Auditory Science to continue providing it in an easy-to-use format for those struggling with putting their babies to sleep beyond July. The free distribution audio source can be used not only for putting babies to sleep at home but also for playing simultaneously over school intercoms during nap times at nursery schools. Furthermore, it can be tried as a sleep aid for all generations, not just children. ■ Benefits of the audiobook.jp App "Background Playback" allowing listening with the screen off Playback continues even when the smartphone screen is dark, eliminating the worry of the screen light waking the baby. "Ad-Free" playback that does not interrupt sleep No advertisements are played during or at the end of playback, preventing the baby from being startled just as they are falling asleep. ■ About the Distri