User blog comment:Silver-Haired Seireitou/Sake Time with Sei - What Came First, the Chicken or the Egg? Wait a Minute.../@comment-30807545-20140905172835

The Rinnegan represents Yin-Yang as most of you would know. From that concept, all things are born, thus the eye's ability to use any and all jutsu known to the Shinobi World. The Sharingan is a component of the Rinnegan, being exactly derived from its parent. It represents the yin of the Yin-Yang, which also deals with the spiritual, unlike its brother, the Byakugan, which deals with the physical and vitality; in this sense - yang, the most extreme example being the Gentle Fist style, which focuses on the body and manipulation of the vitality within, in the form of the Chakra Network. This is shown through its aptitude of genjutsu, which can take on many forms, pending on the users' whim, the many abilities it possesses, such as copying other jutsu and reading the opponent's movements, and the ability to evolve itself under certain conditions - the utter definition being the Mangekyo Sharingan. Thus, the Sharingan is only a small part of the Rinnegan's true power.