When did Sasuke get Rinnegan

Why does Sasuke have 6 points on his Rinnegan?

The Points that They mention their actual name is Tomoe as you said, they are usually formed on Sharingan. Rinnegans are usually characterized by light purple irises with a wave pattern that spreads across the eyeball. Some well-known carriers are Pain (though not really), Nagato, and Madara.

Back to the question, remember that Sasuke received half of Hagoromos (aka Sage of Six Paths) chakra, which was how the Rinnegan was awakened. The Rinnegan Sasuke is quite unique, it has 6 tomoe split between its first two waves, this means nothing, it indicates that the Rinnegan is is fully charged . What's the difference between a typical Rinnegan and a fully charged Rinnegan you ask? Well it's easy. Fully charged Rinnegan wearers like Sasuke gain abilities that typical Rinnegan wearers don't have. Bet you already knew about the skills.

Sasuke cannot use the full capabilities of the Rinnegans if he uses them overused . At this point the tomoe disappears and prevents it from developing its full power. Sasuke will keep his left eye closed until it is fully charged. Sasuke is still able to use his Mangekyo Sharingan's powers with his Rinnegan, but cannot use or sculpt the Mangekyo in his other eye when charged. (See the picture, the Mangekyo does not form on his right eye when it loses Rinnegan's charge, and it forms again when the Rinnegan is fully charged. This is also stated in Narutopedia.)

Here you can see it in the manga.

Eames

Good thank you. I think it's like a counterpart to Naruto's truth seeking bullets

Ryan

Note that Kaguya and Madara both had a similar eye on their forehead, even though it was red instead of purple.

Jeffery Tang

Then why don't Hagoromo or Madara have a Tomoe on their Rinnegan?