Regardless of the chinese fengshui, bazi, zi wei du shu, devinations and many others in the Chinese metaphysics science, all are more or less having the same foundations based on the ancient River Map, Lo Shu, early and later Heaven 8 Trigrams but are also tied up with the lunar calendar 24 seasonal qi for application use.
 
Below diagram is a named "8 seasonal qi into 9 halls" diagram which was created in the ancient China Han dynasty. It basically mapped the 8 main lunar calendar seaonsal qi with the relevant gua trigram on the respective 8 halls. These seasonal qi of the 8 trigrams are also named "gua qi" (being part of the definition) for application use. For example,
  • zhen, xun wood are strong in Spring
  • li fire is strong in Summer
  • qian, dui metal are strong in Autumn
  • kan water is strong in Winter
  • kun, kan earth are strong in chen, xu, chou wei months over the 4 seasons.