All quantities are up to you. Try to get at least a pound of pork bones though.
Pre-Boil pork bones in a large pot and skim off scum as it rises to the top. When most of the scum has come out of the bones, cool them down with running water and scrub off any blood that is stuck to the bones.
Put the cleaned bones into a pressure cooker and cover with water. Pressure cook the bones for 1 hour.
Release the pressure from the pressure cooker after an hour and bring bones to a rolling boil for 2-3 hours, adding water as it evaporates. After 2-3 hours of boiling, cool the soup down and store in the fridge overnight.
The next day add your chicken feet and boil for another 3 hours. Add water as it evaporates.
After boiling the soup for 3 hours with the chicken feet, add the cabbage, round onion, green onion, ginger, galic and niboshi. Boil for another hour Then strain the soup.
To make the bowl of Ie-kei style tonkotsu ramen, add 30ml shoyu tare and 15ml chicken oil to a bowl and add 300-400 ml of the tonkotsu soup.