SOMA-YAKI(ware) MATSUNAGA-KAMA(kiln), The double layer teacup Made in Japan Famous Japanese traditional Pottery SOMA-YAKI that has a tradition of over 300 years size:(D) 2.8inches x (H) 3.5inches Double layer ware:As there is a space between each layer, it does not transmit heat to the topmost layer. So even if you pour hot water, you can easily hold the cup. Blue Cracks:Due to the difference in shrinking percentages of ingredients and glaze, some cracks appear on the surface of the entire vessel with beautiful sound. We use this process in order to make the blue crack patterns on the surface on purpose.