There is a Chipotle knockoff in Roppongi called Frijoles. They have vegetarian black beans, but haven't made their pinto beans pork-free. We saw Frijoles on our walk, so we took a bus the next day to try it out. They offer two sizes for the burrito bowls, so we picked the regular size. It was definitely smaller than American version. It was a few dollars more expensive than the American version too. They had a soda fountain! But it had Pepsi products. I noticed they had a tip box, which is odd because tipping is considered rude in Japan.