|Stage Name||Birth Name||Position||Birthday||Age||Height||Star Sign||C Y||BT Sort descending|
|Hana 하나||Shin Bora||Leader, Dancer, Visual||25||Taurus||Rooster||A|
|Mimi 미미||Jung Mimi||Vocal||25||163 cm or 5'4"||Capricorn||Monkey||B|
|Haebin 해빈||Han Haebin||Vocal||22||Leo||Pig||B|
|Sejeong 세정||Kim Sejeong||Vocal, Visual||21||164 cm or 5'4½"||Virgo||Rat||AB|
|Soyee 소이||Jang Sojin||Vocal||21||Scorpio||Rat||AB|
|Hyeyeon 혜연||Cho Hyeyeon||Maknae||17||167 cm or 5'5½"||Leo||Dragon||O|
|Nayoung 나영||Kim Nayoung||Vocal||22||169 cm or 5'6½"||Sagittarius||Pig||O|
|Sally 샐리||Liu Xie Ning||Sub-vocal||21||Scorpio||Rat||O|
|Mina 미나||Kang Mina||Dancer||18||162 cm or 5'4"||Sagittarius||Hare||O|
Gugudan 구구단, stylized gu9udan, is a female idol group from Jellyfish Entertainment. They are the sister group to VIXX. Just as VIXX was Jellyfish’s first male idol group, Gugudan is Jellyfish’s first female idol group.
Gugudan's mascot is a cute fox-type creature named “Ggyu 뀨.” Ggyu’s role is to deliver news about Gugudan and interact with the fans, similar to VIXX’s Rovix.
For example, there might be Twitter posts that say something like, "Hello, this is Ggyu, letting you know that Gugudan will be coming back on the 13th!"
The phrase 곱셈구구표 means multiplication (kopsem 곱셈), by a factor of 9x9 (googoo 구구), table (pyo 표). The grade school multiplication table demonstrating 1x1 through 9x9 is referred to simply as gugudan 구구단.
Jellyfish Entertainment explained, "Gugudan means that 9 girls with 9 different charms will present performances of hopes and dreams. They will approach the public with familiarity through their bright and pure charms."
In an interview, Hana explained further: "It means the troupe that gathered nine girls with nine charms. It means that we will reinterpret productions of various genres like fairy tales, movies, or plays in a style unique to us and try to perform them."
Regarding how they decided on the name, she said, "We had a contest, and Gugudan was one of the candidates. The chief liked Gugudan and decided on that despite the other employees' opposition."
Mina added, "Honestly, when we first heard that, we were completely taken by surprise, but after saying it, the inner meaning was really nice."
Jellyfish Entertainment used “gx9” in teasers leading up to the official name reveal as an abbreviation for the multiplication table.
Each of the 9 members represents a number on the times table, listed with the pictures above. Each girl is also represented by a unique symbol.
In January 2016, Mnet aired a reality survival show called "Produce 101" where 101 female trainees from various companies competed to debut in an 11-member temporary girl group that would promote for a year under YMC Entertainment. Nayoung, Sejeong, and Mina competed as Jellyfish Entertainment trainees. Sejeong and Mina were accepted into the group and debuted as members of I.O.I. in May of 2016.
Because of YMC Entertainment's special terms in which I.O.I.'s members were allowed to do activities under their respective companies while I.O.I. was on break or while the group promoted in sub-units, Jellyfish Entertainment along with other agencies decided to capitalize on I.O.I.’s popularity by debuting a female idol group that included members who were already members of I.O.I. or had competed on the show.
However, fans of the show were led to believe that all members of I.O.I. would focus solely on the project and promote with their home agency only after the year-long I.O.I. promotions concluded. That led to negative fan reactions at the June 7 announcement of Gugudan’s debut because it came only one month after I.O.I.’s debut. Jellyfish first denied reports of the girls' involvement, only to confirm later that the company’s first female idol group would include Nayoung, Sejeong, and Mina.
Gugudan debuted on June 28, 2016, with the mini-album Act. 1 The Little Mermaid, promoting the release with the song "Wonderland."
Gugudan participated in Jellyfish Entertainment’s winter project, Jelly Christmas 2016, with their label mates Seo Inguk, VIXX, Park Yoonha, Park Jungah, Kim Gyusun, Kim Yewon, and Jiyul. The promotional track "Falling 니가 내려와" was released digitally on December 13, 2016.