Kiron is a planetary asteroid that takes about 50 years to come around to where it was in your birth chart when you were born.

In the Human Design System, we recommend anyone who has completed a deconditioning cycle to get an analysis, especially all 6th line beings. A Chiron Analysis shows the flowering of a 9-Centered Human's potential and is suggested once you have completed a full 7-year cycle in Human Design. It is highly recommended for all 6th line profiles (4/6, 6/2, 6/3) as a priority to know about.

"Chiron, in Greek mythology, one of the Centaurs, the son of the Titan Cronus and Philyra, an Oceanid or sea nymph. Chiron lived at the foot of Mount Pelion in Thessaly. Unlike other Centaurs, who were violent and savage, he was famous for his wisdom and knowledge of medicine. Many Greek heroes, including Heracles, Achilles, Jason, and Asclepius, were instructed by him.

Chiron frequently appears in the legends of his grandson, Peleus, and his great-grandson, Achilles. Accidentally pierced by a poisoned arrow shot by Heracles, he renounced his immortality in favor of Prometheus and was placed among the stars as the constellation Centaurus." ~Source

Personally, my Kironian return Cycle brings me the costume of a 1/3 Cross of Explanation at the age of 49. We generally start to feel the effects of a larger Life Cycle about 3.5 years before and after the Cycle date. However, the Chiron is an element of positive conditioning that reverberates throughout the life; I think of it like echoes from the future. This cycle affects you throughout your lifetime and is particularly present when you’ve made it to the age where Chiron has made a full cycle around the sun. Like all Cycles, it doesn’t change your Human Design Type, Strategy or authority, but it does show us, like a crystal ball, the themes at play, some people you’ll encounter and the movie that speaks to the flowering of your true self.