Boil garlic and red chillies in 2 cups water, for 5 minutes. Drain water, keep aside. Grind chillies,garlic to a paste. Heat oil in a heavy pan. Add ginger, chopped garlic, chopped chillies, stir. Add celery, onions, stirfry till onions are transparent. Add paste, stirfry for 2-3 minutes. Dissolve cornflour in 2 tbsp. water. Add all other ingredients, and drained water from chillies. Bring back to boil, stirring continuously. Simmer for 2-3 minutes, till sauce is thick and smooth. Bottle, cool, refrigerate, use in chinese cooking as required