Runa Akasaka ( Japanese:赤坂 ルナ, Hepburn:Akasaka Runa, born April 7, 1967) is a Japanese actress who is best known for her appearances in adult videos (AV). Akasaka's career in AV lasted about four years, with 70 to 100 videos listed for her at two major retailers  at the end of 2008. Asasaka has also starred in titles in the pink film and V-Cinema genres.
Runa Akasaka made her AV debut in 2003, at the age of 36, in the jukujo or "Mature woman" genre of Japanese adult entertainment. She worked with a number of different studios for the first few months of her career but at the end of 2003 she joined the major Japanese AV studio Moodyz where she starred in such Mature-woman AV titles as A Friend's Mother (友人の母,Yuujin no haha), and The Room Of Two Sexy Madams (W美熟女の部屋,Double bijukujo no heya) for noted AV director Goro Tameike.  
In Spring 2004 she began appearing in videos for the new company Madonna,  an AV studio specializing in the mature woman genre. She made one video a month for Madonna until the end of 2004 when she changed studios again, this time going to KMP.  In August 2005, Akasaka participated in a unique project for the huge AV conglomerate Soft On Demand (SOD), playing the mother in a full-length dramatic adult video, Nightly Continuous DVD Novel. The movie, also starring first-time actress Satozakura Hinata, Aoi, and porn legend Taka Kato, was described by SOD as an industry first at a special screening in Tokyo in July 2005. 
She also appeared in the mainstream men's entertainment magazine Weekly Playboy in 2005.  In 2006, AV Research Laboratory—a non-commercial site specializing in the history of Japanese adult videos—described Akasaka as a popular "veteran" performer in the mature-woman genre, with three years in the industry and over 40 works to her credit. 
In addition to her AV appearances, she also had a leading role in the Okura Films / OP Eiga theatrically released pink film, Molester's Train: Skillful Fingers, Wet Feeling (痴漢電車 いい指・濡れ気分,Chikan densha: iiyubi*nure kimochi) from December 2004,  an entry in the parent company, Shintōhō Eiga's Molester's Train series which Academy Award -winning director Yōjirō Takita started in 1982. By 1997 there had been 25 films made in this long-running pink film series. In their pioneering English-language work on the Japanese erotic cinema, the Weissers write, "Most of the episodes are reminiscent of early American nudie-cuties, especially the voyeuristic titty-flicks like Russ Meyer's Eve and the Handyman and Immoral Mr Teas, or Herschell Gordon Lewis' Adventures Of Lucky Pierre ."