Altogether CoCo Ichibanya, also known as "CoCoIchi," has more than 1,100 restaurants in Japan and about 150 more around the world, serving up unusual curries such as sausage; hamburger; and tomato and asparagus.

Back in Japan it's a household name, but Ichibanya hasn't ventured into Europe until now.

Its first U.K. outpost opened last December in London's Covent Garden, where diners are already lining up to try Ichibanya's unique offerings. After choosing a topping (options include fried chicken dumpling; kimchi; or bubble-fried salmon) diners then decide the level of heat. Ichibanya's sauce options range from "Standard" to "Level 5 Crazy Hot."