What is a mochi pestle?

A mochi pestle, known as "usu" in Japanese, is a traditional tool used to pound glutinous rice into mochi, a chewy rice cake. Typically made from wood or stone, it is designed for effective grinding and mixing during the mochi-making process. The pestle is used in conjunction with a mortar, called "kine," to create a smooth, sticky texture that is characteristic of mochi. This process is often a communal activity, especially during celebrations like the Japanese New Year.