In order to prevent the head of the pestle from chipping and any small piece of wood from contaminating mochi, the head of the pestle is put in a bucket filled with water to cause the pestle to absorb sufficient water before pounding mochi.
餅搗きをする前に杵の頭が欠けたり木片が餅に入るのを防ぐために水を張った桶の中に杵の頭を漬けて水分を含ませておく。