N
Google
Arrived 10.35 on a Wednesday in May and there were already 10 people in the queue. They start letting people in at 11:05 or so, and as others have noted there are only 11 seats, 6 of them at the bar (they start filling the tables first). After you're let in, you'll have to order and pay at the machine inside (card only, English translation available) before sitting down. You can order individual items apart from the set meal if you want to try other items on the menu.
Expect to be served within 10mins. The loin and the chicken were very tender, well seasoned and cooked perfectly. The chef and the lady attending were welcoming and attentive, and offer cabbage refills. The lady also speaks good English and can help answer your questions.
By opening time there were about 20 people in the queue. The first batch of diners start leaving at around 11:30, and they start cleaning tables right away. By the time I left at 12:00 there were 15 people in the queue outside. Note that some menu items run out so you may have more limited choices if you arrive later.
You may have to queue under the sun so bring an umbrella if you don't like that.
Overall it was a very good meal, but if you don't like queuing, you will find others of similar quality in Tokyo.