This is an Arita-yaki kyusu (teapot) decorated with sometsuke doji-mon (blue and white painted children). This design is often seen in works from Arita-yaki kilns such as Gazan-gama and Nabeshima Kazan. The scene of children playing is depicted in indigo, a traditional Japanese design. It is a collector's item, often traded as a vintage or antique item. It is a traditional tea utensil for brewing Japanese tea. This item has been stored at home for a long time. Please purchase if you understand this.