Soak the beans and the kombu in a large pot of water overnight.
In the morning, drain and rinse the beans. Return them to a large pot and add 3 cups of water plus the kombu.
Simmer gently for an hour, or until the beans begin to get tender.
Remove the kombu and add the remaining ingredients to the pot. Simmer uncovered over low heat for another 30 to 40 minutes, until the mixture thickens. Serve warm.