Cage Force
Around , GCM Communication, the parent company of Japanese promotion Cage Force, had already hosted some all-women MMA events named "Cross Section" and with the imminent dissolution of female MMA promotion Smackgirl, GCM Communication announced at the event "Cage Force 08" on that the company would hold a new all-female promotion which would be named Valkyrie and would have its first event on in a double-header event with Cage Force. Takeshi Nagao, a former Smackgirl executive, and Yasuko Mogi were appointed as producers. Mogi announced several details of the promotion, such as the weight classes and the rules, which would be essentially the same as those used in Cage Force, and also that former Smackgirl Lightweight Champion Yuka Tsuji would participate in the promotion in a match against Mei Yamaguchi. Other matches would be announced at later dates. As part of its business strategy, Valkyrie events were held before Cage Force, in this way sharing venue, cage and other resources.