Chikayo Nagashima is a Japanese professional wrestler. She started her career in 1995, working for the Gaea Japan promotion, where she became a one-time AAAW Single Champion and a record five-time AAAW Tag Team Champion. She was also notably one of the four founding members of the Oz Academy stable. Following the folding of Gaea Japan in 2005, Nagashima affiliated herself with Oz Academy, now a full-time promotion, where she has become a three-time Oz Academy Tag Team Champion and a one-time Oz Academy Openweight Champion, holding the record for the longest reign in the title's history. Nagashima remained with Oz Academy until August 2015, after which she became a freelancer.

The AAAW Single Championship or AAAW Championship is a women's professional wrestling championship formerly contested in the Japanese women's professional wrestling promotion Gaea Japan until 2005 after the promotion was closed down. Originally a heavyweight championship, the weight class was dropped in 1998, making it an openweight title. On March 12, 2021 it was announced that the AAAW Singles Championship would be revived, along with the AAAW Tag Team Championship, at the GAEAISM show on April 29. It was revived in January 2022 and began being sanctioned by Marvelous That's Women Pro Wrestling ever since.