Rinse dried scallops under running water; Soak them in water for 15 minutes; Remove them; Fill a bowl with 200ml water; Put the dried scallops in the bowl of water; Leave it for 3 hours.
Rinse dried shrimps under running water; Soak them in water for 15 minutes; Remove them; Fill a bowl with 300ml water; Add the dried shrimps; Leave it for an hour.
Rinse and drain a carrot; Trim a bit off each base; Peel it with a Y-shaped peeler; Rinse it under running water; Drain it; Cut it into chunks.
Remove husks of corn; Rinse and drain it; Cut it into sections.
Rinse celery under running water; Drain it; Trim a bit off the bottom; Pull off the outer leaves and tough stalks; Discard any wilted leaves; Cut the remaining into sections; Rinse them under running water again; Drain them.
Rinse fresh button mushrooms under running water; Pat-dry them with kitchen paper; Scrape off any dirt with a vegetable knife.
Rinse and drain tomatoes; Discard any stems; Cut each into quarters.
Fill a stockpot with 2L water; Bring to the boil over a high heat; Add the carrot, the tomatoes, the corn, the dried scallops and the dried shrimps (including 200ml dried scallops soaking water and 300ml dried shrimps soaking water), and bring to the boil over a high heat again; Turn to a low heat; Cover the pot with its lid; Cook over a low heat for 1.5 hours; Add all the remaining ingredients, and bring to the boil over a high heat again; Stir seasoning into the soup; Turn off the heat; Arrange the soup in serving bowls; Ready to serve.