What is 'chashu' and how is it made?

Chashu is a popular ramen topping made from pork belly that is braised in a sweet and savory sauce. The pork is rolled into a log, tied with string, and then simmered in a mixture of soy sauce, mirin, sake, and sugar until it's tender and flavorful. The chashu is then sliced thinly and served on top of the ramen. The rich, fatty pork is a perfect complement to the savory broth and springy noodles.