If you don t have kombu or dashi, use chicken or fish stock. Actually, any lightly seasoned broth or even plain salted water is fine. Be very careful whenever cooking at the table. Protect the table from the heat source, and keep electrical cords well out of the way. I like to use a tabletop butane gas burner, but an electric hot plate or electric pan is fine.
Tall pots impede access.
Place the platters of ingredients within easy reach of all diners. Set out individual bowls of dipping sauce and let people add whatever condiments they like to their dipping sauce. Heat the stock to a simmer, then add ingredients a few at a time, beginning with the ones that need the most time to cook. Since most ingredients need only a minute or so, do not add ingredients faster than people can eat them. Each person removes food as it is cooked from the pot, dips it in sauce and eats it.