This is an old piece, likely Gosu Akae (red underglaze) from the Ko kiln in Hasami. It has the mark "Ko" on the back. Size: Approximately 15.5cm x 13.8cm x 5cm The following is from the Kyoryu Toki website in Hasami Town: Gosu Akae, born from the traditional techniques and aesthetic sense of Arita ware, has been loved for generations. It features an elegant pattern entirely painted with Gosu (blue underglaze) and red enamel.