Language difficulties make it hard to research rallying in Japan, but there are at least a few female drivers active on the domestic scene. This post will hopefully be expanded in future.
Rina Ito – active in Japanese and Asia-Pacific rallying since 2010, usually driving a Mazda 2 Demio. She took part in the Rally of Hokkaido in 2011, and is listed as an entrant for the 2012 Asia Pacific Rally Championship, although the results are proving elusive. She had a decent season in Japanese rallying in 2013, with a best finish of 24th, in the Osaka University Tango Peninsula Tango Rally. In 2013, she equalled this result, in the Hokkaido Rally, still in the Mazda. That year, she competed overseas in the New Zealand Rally, in a Honda Civic, but had an off on the final stage. She continued to rally in 2015, mostly in Japan, but with one run in the Rally of Whangerei, in New Zealand, which she did not finish. Her best finish was 27th, in the Fukushima Rally. In 2016, she entered the Shinshiro Rally, in a Toyota Aqua. She was 42nd overall. She drove another Toyota, a Vitz, in 2017, and earned her first top-twenty finish: 20th in the Kumakogen Rally. Rina had an unusual introduction to motorsport, starting out as a Super GT grid girl.
Kozue Oi - Japanese international driver. She began her WRC career in Kenya in 2000, in a Subaru Forester. Since then, she has driven in WRC events in Japan and New Zealand, as well as the Japanese and Asia Pacific championships. She also drives in Malaysian rallies. Her cars have included a Subaru Impreza, Mitsubishi Lancer and Ford Fiesta. In 2009, she drove a Mitsubishi Colt in the Japan Rally Series, which she won, driving for the MusicMasters team, after a string of good finishes. She drove in the Wales Rally GB for the first time in 2009. As well as rallying, she has won multiple titles in off-road trials in Japan.
Fumi Shimada – rallied a Mazda 2 Demio in Japan, in 2013 and 2014. She did reasonably well in her first season, scoring two top-twenty finishes, the best of these being an 18th in the Osaka University Tango Peninsula Charity Rally. She was also 20th in the MCSC Rally Highland Masters, fifth in class. In 2014, she did not do quite as well, and had a best finish of 29th, in the Shinshiro Rally. In 2015, she rallied the Demio again, and managed to finish the MSCC Rally Highland Master in 25 place, second in class. For 2016, her schedule was very similar. She was 27th in the both the MSCC event, and the Shinshiro Rally, and 32nd in the Wakasa Rally. In 2017, she only entered one rally, the Shinshiro Rally, and did not finish. Her navigator is usually Yusuke Ishiguro.
(Image from http://cdn.mkimg.carview.co.jp)