Woodblock illustration of 'Baked centre' tongue (
zhongbei she) from
Yuan Ao Shi shanghan jinjinglu (Mr Yuan Ao's Golden Mirror of Cold Damage), a treatise on tongue diagnosis -- original text by Ao Jiweng (Song period, 960-1279); additional material by Du Ben (Tao Hua) (Yuan period, 1206-1368 ); continuation by Xue Ji and Ma Chongru (Ming period 1368-1644). This edition was published in 529 (8th year of the Jiajing reign period of the Ming dynasty).
The text states: 'Baked centre' tongue image is red with a black shape inside it like another smaller tongue. This tongue image shows that heat malignity is established inside the body, and fire is raging in the heart. Appropriate treatments are Diaphragm Cooling Powder (liang ge san) and Major Bupleurum Decoction (da chaihu tang) to purge the heat.