Kaori Yoneyama
In August, Nakajima became one of the key members of the JWP Seikigun ("regular army"), during the promotion's storyline rivalry with Emi Sakura and Kaori Yoneyama, representing the Gatoh Move Pro Wrestling promotion. After being defeated by Sakura in a singles match August 12, Nakajima and fellow Seikigun member Command Bolshoi defeated Sakura and Yoneyama on August 19 to win the JWP Tag Team and Daily Sports Women's Tag Team Championships. Nakajima and Bolshoi made their first successful title defense on September 9, defeating Leon and Ray. On October 7, the JWP Seikigun, represented by Nakajima, Bolshoi, Kayoko Haruyama and Manami Katsu, were defeated in an eight-woman captain's fall elimination tag team main event by Emi Sakura's and Kaori Yoneyama's new Heart Move Kei Reform (HMK) stable, which in addition to the two also included Hanako Nakamori and Morii. Nakajima was the only JWP representative not eliminated from the match. On October 28, Nakajima and Bolshoi successfully defended their titles against Nakamori and Morii. Following the main event, where HMK member Emi Sakura captured the JWP Openweight Championship from Kayoko Haruyama, Nakajima entered the ring and made a challenge for the title. On November 11, Nakajima defeated Morii and Nakamori in a four-woman tournament to become the number one contender to the JWP Openweight Championship. En route to the title match, Nakajima was pinned for the win by Kaori Yoneyama in an eight-woman captain's fall elimination tag team main event between JWP and HMK on December 2. On December 24, Nakajima capped off her return year by defeating Emi Sakura to win the JWP Openweight Championship for the first time. Afterwards, the bloody champion, thirteen years younger than her opponent and the second youngest JWP Openweight Champion in history, announced that she wanted to defend the title against wrestlers from her own generation. Three days later, Nakajima was named JWP's MVP of 2012, while her and Bolshoi's tag team title match with Sakura and Yoneyama from August 19 was named the Match of the Year.