In a large pot of boiling water, cook potatoes for 15 minutes. Peel the potatoes and then chop into large cubes. In a large pot of cold water, cook eggs on medium heat until water boils then let boil for another 5 minutes. Remove eggs from the pot and let cool in a bowl of cold water for 10 minutes. Remove egg shells and slice 2 eggs in an egg slicer. Chop the remaining 3 eggs into cubes.
Chop 3 tomatoes into cubes and 1 tomato into round slices. Chop celery into cubes. In a large pot of boiling water, cook shrimp and scallop for 1 minute then remove immediately.
Combine all ingredients, mayonnaise, salt, pepper, sugar, chicken bouillon, wasabi, and lemon juice. Mix well.