Takashi Nagasaki (長崎尚志, born January 14, 1956) is a Japanese author, manga writer and former editor of manga. He started his professional career at Shogakukan in 1980 and worked as an editor on the publisher's various manga magazines, including as editor-in-chief of Big Comic Spirits from July 1999 to 2001. Since becoming freelance, Nagasaki has worked as an author under various pen names, such as Keishi Edogawa (江戸川啓視), Garaku Toshusai (東周斎雅楽), Big O (ビッグ・オー) and Richard Woo (リチャード・ウー).