Sachiko is a Japanese VOCALOID developed and distributed by YAMAHA Corporation, and was released in July 2015 for the VOCALOID4 engine. She was voiced by Japanese voice actress, actress, and one of the leading enka singers in Japan, Sachiko Kobayashi.
Her design was done in collaboration with YAMAHA and Sachiko Kobayashi to create a singer who represents Japan.
The calligraphy kanji 幸 (sachi) on the fan was written by Sachiko Kobayashi herself.
Her Obi is worn backwards. This was a style of clothing made popular with the Oiran courtesans.
According to her product page on the VOCALOID Shop, Midori Fuu said that Sachiko's kimono and headdress is based off the Yukitsubaki (snow camellia): the official flower of Niigata Prefecture which is Sachiko Kobayashi's hometown. It also references the title of one of Sachiko Kobayashi's hit songs.
Due to the popularity and fame of Sachiko Kobayashi in the Japanese culture and music industry, the VOCALOID was met with much excitement among Japanese fans. At the time, Kobayashi's profile as a singer was considered as one of the highest among the VOCALOID singers sampled for the software.