How many years does it take to learn Yi to count as luck?

/kloc-Learn some fur in 0/0 year, learn some basics in 20 years, learn some knowledge in 30 years, sum up experience in 40 years, and be a master in 50 years.

It takes at least 200 years to learn the Book of Changes, because there are too many sects, such as divination, horoscope, geomantic omen, palm reading, Daoism, Yilin, divination, reflection, plum blossom easy counting and so on.