Naruko is a word that originated in Japan, which refers to a traditional instrument used in Japanese festivals. The instrument is made of wood, metal or bamboo and has a specific sound that is used to signal various events during the festival. There are several synonyms for the word naruko, including kachi-kachi, kara-kara, and katsugi. Some other synonyms include chappa, which is a similar instrument used in Okinawa, and sasara, which is a type of rattling instrument used in Japanese folk music. These instruments may have different appearances, but they serve the same purpose of adding rhythm and excitement to Japanese festivals.