Bring the dashi just to a boil over high heat, then simmer. Add salt to taste. Add soy sauce. Mix cornstarch and 3 tablespoons water, and add this mixture to the soup. Stir for 30 seconds, and bring to medium heat.

Beat the eggs, and drizzle them over the soup. Let the egg set, and stir the soup gently with a wire wisk. Add the ginger juice.

Pour hot water into the laquer bowls, and let stand 2 minutes. Drain. Fill each bowl 3/4 full, and garnish with watercress. Serve immediately.

This recipe yields ?? servings.