Method
Remove the stem part of red chillies, cut open and remove the seeds and soak them in hot water. Deseeding is optional, but chose to remove them to reduce the spicyness a bit. Soak red chillies atleast for 30 mins.

Then drain red chillies and transfer it to a mixer. Add the drained water to the mixer.
Grind it to a fine paste.

Add water little by little and keep grinding till you get a smooth paste, Set aside.

Fine chop garlic and ginger. Heat oil in a pan - add chopped ginger and garlic and fry for 2 mins without changing the colour.

Then add red chilli paste and let it boil in low flame for 3-5 mins till oil starts leaving. Then add soya sauce.

Then add vinegar, tomato sauce, black pepper powder and required salt and cook for 5 mins in low flame. Switch off.

Cool down completely and store in airtight jar.