I made a reservation a few weeks ahead of time.Definitely go for the bar and not the table if it's still available. I think they only seat 2-3 dinners a night and the restaurant fits around 18 people. We ended up getting a table and wish we got a seat at the bar. The bar gives you a great view of the chefs and they explain the fish and food to you. The dinner lasts about 2.5 hours and has 16 pieces of sushi. At the end they'll ask you if you want extras for an additional price.
Definitely worth trying!