Battle Girls: Time Paradox

Battle Girls: Time Paradox, known in Japan as Sengoku Otome: Momoiro Paradox (戦国乙女～桃色パラドックス～, Sengoku Otome ~Momoiro Paradokkusu~, lit. "Warring States Maidens: Pink Paradox"), is a 2011 Japanese anime television series based on the CR Sengoku Otome pachinko game series developed by Heiwa. Produced by TMS Entertainment under the direction of Hideki Okamoto, the anime series aired on TV Tokyo between April 4, 2011 and June 27, 2011. The series has been licensed in North America by Sentai Filmworks. A video game based on the series, Sengoku Otome: Battle Legends, will be released for PlayStation Vita on August 25, 2016.

Plot
Modern-day middle school girl Hideyoshi is mysteriously hurled into a world resembling the warring states period of Japanese history, only this time it's inhabited only by women. This world's Oda Nobunaga is gathering the legendary Crimson Armor so she can rule the world, and for some reason needs Hideyoshi's help to do it.

Other Sources
http://www.animenewsnetwork.com/encyclopedia/anime.php?id=12506