The term "shikyo" refers to the four historical stories (history books with a narrative style) generically known as 'kagami-mono' (mirror works), which includes "O-kagami" (the Great Mirror), "Ima-kagami" (the Mirror of the Present), "Mizu-kagami" (the Water Mirror), and "Masu-kagami" (the Clear Mirror), that appeared between the late Heian period and the early Muromachi period.
四鏡（しきょう）は平安時代後期から室町時代前期までに成立した「鏡物（かがみもの）」と呼ばれる『大鏡』・『今鏡』・『水鏡』・『増鏡』の4つの歴史物語（歴史書）。