For sesame dipping sauce, combine ingredients in a bowl and season to taste.
For citrus-soy dipping sauce, combine ingredients in a bowl and season to taste.
For stock, combine ingredients in a hot pot or large saucepan and bring to a simmer. Season to taste and place in the centre of the table on a portable gas burner.
To serve, arrange a small bowl of each dipping sauce and a dish of spring onion and cress for each guest. Dip slices of wagyu into stock until cooked to your liking (10 seconds for medium-rare), then dip into your preferred sauce. Meanwhile, add watercress, mushrooms and tofu to stock to warm, then repeat.
