Xiang-Shu thinking in Yun-Qi theory in Huangdi’s Canon of Medicine

The characteristic of Xiang( image)-Shu( number) thinking was reflected in Yun-Qi theory( doctrine of the five circuit phases and six atmospheric influences) in Huangdi’s Canon of Medicine in the following aspects: the pattern of Yun-Qi,understanding of climate and phenophase,understanding of incidence of diseases,and understanding and application of medicines. In this theory,property of Xiang was systematically assigned to Shu,and Xiang and Shu were organized in a unique and complicated way to establish Yun-Qi pattern,by which climate,phenophase and incidence of diseases at a specific time were calculated,on the other hand,the status of Yun-Qi pattern was back-calculated based on metaphorical meaning of climate and phenophase. Xiang-Shu thinking also ran through the understanding and application of medicines of Yun-Qi theory,consequently different with later Chinese materia medica. So,the way of Xiang-Shu thinking would be helpful to master and apply Yun-Qi theory.