When someone talks as if he or she is reading a script, but in fact is improvising his or her speech, the expression 'kanjincho' is used, which is derived from the Scene of Reading Kanjincho Aloud, where Benkei pretends to read the scroll he happened to have with him aloud and sonorously.
弁慶が「読み上げ」で持ち合わせの巻物を朗々と読み上げる場面の連想から、あたかも原稿を読んでいるようで実は即興でものを言っているさまを、「勧進帳」という。