At each year November(11/1), water star shows on the north sky, it is winter, there is ice on the earth. So, sky(yang) 1st(November) born water, earth(yin) 6th hold it.Which is: 1-->6.
At each year July(7), fire star shows on the south sky, it is summer, it is very hot weather like fire on the earth. So, earth(yin) 2nd born fire, sky(yang) 7th(July) hold it. Which is: 7-->2.
At each year March(3), wood star shows on the east sky, it is spring, wood grow on the earth. So,sky(yang) 3rd(March) born wood, earth(yin) 8th hold it. Which is: 3-->8.
At each year September(9), metal star shows on the west sky, it is Fall, Fall weather like metal cool down and sink down everything on the earth. So,Earth(yin) 4th born metal, sky(yang) 9th(September) hold it. Which is: 9-->4.
At each year May(5), earth star shows on the center sky, it is the damp heat weather, five elements all on the center earth location. So, Sky(yang) 5th(May) born earth, earth(yin) 10th hold it. Which is Center 5/10.