Hikaru Koto / Hikaru Coto (古都 ひかる,Koto Hikaru) is a Japanese web personality, photographer and a former AV idol and gravure model.

Koto made her adult video (AV) debut at age eighteen in the September 2003 release, Virgin Princess - natural (処女宮 -natural-) on the h.m.p. /Platinum Tiffany label. ^[5] In her first year as an AV actress, Koto had sales of more than a million volumes. ^[7] At the end of 2012, listed 89 DVDs of her performances, as well as several books.

Because of her youth, Koto was often presented in cosplay roles as a high-school girl as can be seen in the May 2004 release Ero Comic. ^[9] In her June 2004 video, Indecent Attraction, the plot has her being hypnotized to become a nymphomaniac (the box title proclaims "She became a beast"). One of her male companions is famous AV actor Chocoball Mukai. ^[10]

In February 2005 Koto was given the Best Actress Grand Prize at the 2005 Adult Broadcasting Awards for her work on the Rainbow Channel in the 2004 broadcasting season. ^[13] She spent her entire AV career working for h.m.p. and released her last original video with them in July 2004. A 4 volume DVD compilation of her complete works was released by h.m.p. in July and August 2005. ^[15]

Despite having retired from AV in 2004, when the major Japanese adult video distributor DMM held a poll of its customers in 2012 to choose the 100 all-time best AV actresses to celebrate the 30th anniversary of adult videos in Japan, Koto finished in 6th place. ^[16]

Since retiring from the adult industry, Koto has become one of Japan's most popular YouTube personalities under the name "cotorich" and is known for her frequent use of "Ohayō. Konnichiwa. Konbanwa". ^{[7] [18] [2]} Also under the name Cotorich, Koto has started a career as a photographer and has published two volumes of her photos as COTORINRI (2010) and COTORINRI 2 (2011). She won an award for excellence for her work at the 14th Photo Exhibition sponsored by the Kokusaibunkakarejji (国際文化カレッジ) foundation. ^{[2] [2]}