What does China's ancient Book of Changes mean by having a two-year birthday?

The theory of life is based on sound. Sixty jiazi, the sound is only thirty, so I played the same sound for two years. Such as Jiazi (1984) and Yigou (1985). That is, people born in Jiazi (1984) and Ugly (1985) are destined to be in the sea.

So, once every two years.

Note: Yin Na's original book is marked with five tones and six methods, so it is borrowed here to discuss fate.

Good luck.