SiS (Shimizu Idol Society) was a short-lived idol group, originally conceived as a sister group for the newly-reformed BiS in 2016. They disbanded the day after their first performance in September 2016. 3 of the members later joined GANG PARADE under different stage names in November 2016.
- Coco Chanel (Now in GANG PARADE)
- Chin Mirei (Now in GANG PARADE)
- Son Shion (Now in GANG PARADE)
- Bug Me (Left before debut)
Upon the results of the BiS Reformation Audition, all boot camp finalists who were not chosen for BiS were invited to join a sister group, SiS. SiS would not be produced by Watanabe, instead, they were to be produced by former Especia producer, Hiromitsu Shimizu. Of the runners-up, "Michihayashi Rio", "Second Summer Uika", "Terayama Yufu", "Hirano Nozomu" and "Bug Me" all accepted the offer. During the reformed BiS' debut live that same night, Michihayashi, Second Summer and Hirano appeared onstage and declared themselves BiS' rivals, with their debut live happening late September. Some time afterward, Bug Me withdrew from the group.
SiS had their free debut live, "This is SiS", on September 25th. There, they revealed their stage names as "Coco Chanel" (Michihayashi), "Chin Mirei" (Second Summer), "Son Shion" (Terayama) and "Kanabun" (Hirano).
Unfortunately, just one day after their debut concert, it was announced on their Twitter that the group would disband immediately due to misbehaviour from their manager.
In early October, it was announced that Coco Chanel, Chin Mirei and Son Shion had joined GANG PARADE.
In February, WHO KiLLED IDOL? -SiS Shoumetsu no Uta-, a documentary about the group, was released to certain theatres.
- [2016.09.24] AKG
- [2016.09.24] Kurosawa (クロサワ)
- [2016.09.24] Dosei (どせい; Saturn)
- The SiS members who migrated to GANG PARADE still occasionally do small events as SiS, however, their discography has never been performed or released since their debut live.
- Bug Me later took part in Miss iD 2019.