黛敏郎 = Toshiro Mayuzumi, 宮内庁式部職楽部, The Music Department Of The Imperial Household - 昭和天平楽 = Showa-Tempyo-Raku FLAC album

One of the volumes from the Victor Japan series' Contemporary Music of Japan.
Among them are some legendary issues by Takemitsu, Mayuzumi, Moroi, Ishii, Yuasa and others.
For instance it includes the celebrated original pressing of "Experimental Music of Japan": https://www.discogs.com/Various-Experimental-Music-Of-Japan/release/3133167
Like many other volumes in that series, this LP is devoted to works using traditional instruments, in that case one of Toshiba Mayuzumi's works with Gagaku.
For sure a great series that reflects the rediscover of traditional aesthetics by the post-war composers.