Kawaguchi Yurina

 (川口ゆりな) is a former member of X21.

As of July 2021, she is confirmed to be a contestant on MNET's girl group survival show, Girls Planet 999.

2016 - 2018: X21
She joined X21 in April 2016 as a 2nd generation member and was among the final lineup when the group eventually disbanded.

2021: Girls Planet 999
In May 2021, she was spotted in South Korea and was identified as a possible contestant on MNET's girl group survival show Girls Planet 999. Later on July 8, 2021 she was officially identified and confirmed as a contestant of Girls Planet 999. She ranked 9th out of the Japanese trainees during the signal song evaluation.

Singles

 * Natsu dayo!!
 * Kagami no Naka no Parallel Girl
 * Genjitsu kara Nigeru kara Genjitsu ga Tsurainda
 * Friday Night Party
 * Destiny

Digital Singles

 * O.O.O