What do you mean by Yang Dun's fourth inning?

The fourth game of Yin is one of the eighteen games of Dunga. After beginning of spring used the Yang Bureau, Xia Hou's six weapons entered the fourth palace of Xun, and other stars flew to the ninth palace, forming the territory of the fourth bureau of Yin. Substitute time, and arrange the world of Yin and Si in Taoist magic according to the method of adding temporary workers on the tenth day ~