The song "Namida no Tokyo" (Tokyo in Tears) is a pretty rollicking Group Sounds song in itself but it's the makeup of the GS band Shin Saegusa with Day & Nights（三枝伸とデイ＆ナイツ）that first caught my eye.
For one thing, it's a pretty large band with eight members, and for another, there are two female members in Day & Nights. Of course, there have been the male-only groups such as The Spiders and The Tigers, and I've even heard of the more obscure female Group Sounds bands which have yet to be covered on the blog. But I had never heard of a GS outfit that had both men and women...until Saegusa with his Day & Nights.
They debuted with the February 1967 "Namida no Tokyo", a GS-appropriate twangy song about how cruel the big city can be in the world of love. It was written and composed by leader Saegusa who was behind most of their songs as the songwriter, and although the female members just come in here for this particular song with the background chorus, they do add to the high end of the harmonies to the extent that I'm left wondering about why couldn't there have been more mixed GS groups. Maybe there were but at this time, I only know about Day & Nights. I'm also curious as to whether the women had their time as lead vocalists.
Not much information is available for the group although the Showa Pops Encyclopedia shows that the group only released four singles up to the following year in 1968. J-Wiki has an article on one of the members, guitarist Shuu Tanaka（田中収）who would later become the leader and vocalist of his own band, the so-called New Adult Music group Nyc Nyusa（ニック・ニューサ）that debuted with "Sachiko"（サチコ）in 1981. Earlier on, Tanaka has also had his stint producing entertainers such as Finger Five.