Put the water and onion, tomato, and tamarind in a casserole. Let it boil for 20 minutes.
Remove the tamarind.
Mix the pork belly in the boiling water and cook it for 45 minutes.
Add the taro root and pepper. Cook it for 10 minutes.
Add the kangkong and patis. Cook it for 2 minutes.
Serve this with rice.