Issaku is a restaurant brand in Niigata Prefecture, Japan, offering private dining for families, friends, couples, and group gatherings. Its restaurants feature fully private rooms, creating a comfortable setting for everyday meals, celebrations, and banquets. The brand welcomes guests of different ages and aims to pair flavorful food with warm, attentive service.

Issaku offers more than 800 menu items, with choices designed to appeal to everyone from children to older diners. Fresh ingredients characteristic of Niigata are prepared in the restaurants, where dishes are made to provide a fresh dining experience. Popular selections include demi-glace omelet rice, a colorful assortment meal, Issaku ramen, pepper rice with top blade steak, and the special Issaku set meal.

The company operates locations including Itoigawa Nunagawa, Joetsu Inter, Myoko Arai, Nagaoka Higashi, Nagaoka Nanokamachi, Tsubame-Sanjo, and Niigata Matsuzaki, as well as a location at Aeon Mall Niigata Kameda Inter. Issaku also shares menu information, restaurant updates, and details about its dining concept through its official website.