This 7-seater restaurant in the basement of a building in Nishi-Azabu - around 15 minutes' walk from Roppongi Junction - is popular among locals and foreigners and often requires reservation weeks in advance, unless you don't mind eating a bit late. I had my dinner booked for 9:30pm, which turned out working well for me as I had more time to run chores after work, and for the most part I was their only customer during that time slot.