Open 24 hours, 7 days a week, this Korean place seems to serve its limited menu mainly to Koreans working in the Akasaka area (of which there are many, especially at night. That's why there were various tables of women with big hair and fur coats even late at night.). It's tasty and soothing, a healthier alternative to other things you might eat late at night.
The house specialty is this soup called Sol Ron Tan (雪濃湯, "heavy snow soup" or words to that effect), which I think gets its delicate flavor and milky-white color from boiled beef bones. For something made from bits 'n' bobs, it really is mild. Into the soup go a few green onions, some clear bean noodles, and a few slices of braised beef. You can order more meat if you want to toughen things up a bit. This being Korean food, you get a good assortment of snacks (perhaps 10 in this case) based on vegetables and chili. I don't mean to imply that everything is kimchee; it's not by any stretch, as there are are fried bean sprouts, lightly crunchy and sweet black beans, and other healthy nibbles.
The rest of the menu is only 3 items - more of the beef, or the classic Korean pancake, or more of the clear bean noodles, this time pan-fried with some vegetables and soy sauce to make a heavy and sticky but still mild and soothing bowl. Prices are a little high for late-night comfort food, but this is because the side dishes are so varied and nice. Good any time of day.