Marinade chicken with ½ tsp salt, ½ tea spoon black pepper powder, ½ tsp red chili powder and 2 tsp soya sauce for 30 minutes.
Heat 2 tbsp. oil in pan and fry chicken until soft. Remove in a plate.
Add 2 tsp oil in same pan. Add minced garlic and sauté until gives an aroma. Now add tamarind juice, salt, vinegar, hot sauce, sugar, remaining black pepper powder, and red chili powder and ketchup. Stir well.
When it starts bubble, add water according to the thick gravy you want. Cook it for 2 minutes.
Then add cube capsicum and onion; cook for 5 minutes or until half cook.
Now add chicken and cook until vegetables are done.
If you want thick gravy add corn flour paste.
Dish it out and serve with chicken fried rice.