This recipe is Slovak version of the Sauerkraut soup which is traditionally served during Christmas festivities. No one is more associated with sauerkraut than Gemans but they didn't invent this dish and there is tons of variations of this recipe across Europe. Over 2000 years ago the Chinese were building the great wall of China and needed to feed thousands of workers in a remote area. They found probably one of the most remarkable things about cabbage that you can preserve it with no refrigeration or canning by fermenting it. They didn't use salt, probably because salt was scarce back then, but they used a rice wine to ferment and preserve the cabbage and it was a nutritious dish that fed the workers and kept them healthy and strong.