Oil Spotted Tenmoku Bowl Tenmoku originated from China's Han Dynasty through to the Tang Dynasty, where development in brown glazed wares took place. The perfection of the firing technique during the Song Dynasty allowed for a thicker and more mature glaze layer. Tenmoku is a stoneware glaze which is deeply stained by iron oxide. Tenmoku wares usually have dark brown and black glazes scattered with rust patches, but can come in yellow, green or purple coloured glazes too. Tenmoku glaze is best known for its expressive depth and variation of colour.