Thanks for the info about the album, Alienpyon!
So who is HATTORI, Ryoichi (服部良一)? Quoting from farsidemusic.com:
The Jp Wikipedia page says "日本のポップス界隆盛の最大の功労者である," which means something like "the largest meritorious person of the pop boundary prosperity of Japan" according to Google Translate. And I was surprised to find a Time magazine article dated back to 1949 (Wow! -- Often times if you're looking for things dated before 1990, the librarian will just point you to the microfilm section) , which says "Ryoichi Hattori, 43, a jolly, wavey-haired fellow whom many Japanese jazz composers call sensei (teacher)." [That article was an interesting read. Or maybe it's an indication that I'm getting old...]...Ryoichi Hattori (1907-1993), thought of as the originator of Japanese modern popular songs who laid the foundation for post-war enka. The word blues became known in Japan when in 1937 Ryoichi Hattori composed Wakare no Blues (Seperation Blues) for Noriko Awaya..., as well as Hamako Watanabe & Noboru Kirishima's "Soshu Yakyoku* (Suzhou Serenade)" (1940), Shizuko Kasagi's "Tokyo Boogie-Woogie" (1947), Hideko Takamine's "Ginza Kan Kan Musume (Ginza Street Girl)" (1949), Ichiro Fujiyama & Mitsue Nara's "Aoi Sanmyaku (Blue Mountain Range)" (1949) and many others.
The album is a tribute to Ryoichi Hattori, to commemorate his 100th anniversary. (Source.) [IMHO, it to some extent can be seen as Ayaya's honor to have been selected to participate in this album.]
*Two clips of 蘇州夜曲 (Soshu Yakyoku) @ YouTube: one by Ueto Aya, and the other by 李香蘭 (Li Xianglan.)