《黄帝内经·素问·六元正纪大论》
司天之气为燥化，五运成数为九，表示太过；年运和在泉之气均为热化，五运生数为二，表示不及。
其化上苦温，中辛温，下甘热，药食宜也。
The Qi of controlling the sky is dry transformation, five-element generation number is nine, indicating that it is too much; the annual frequency and the Qi in the spring are both hot transformation, five-element generation number is two, indicating that it is insufficient.