Prepare Pork Bones: Soak pork bones for a few hours to overnight to draw out impurities. Rinse well after soaking.
Pre-boil Bones: Boil bones in a pot, skimming off scum until only white scum remains. Rinse bones again after dumping the water.
Pressure Cook: Place cleaned bones in a pressure cooker, cover with 3.5L of water, and cook on high for one hour.
Add Aromatics: After pressure cooking, add 1L of water, cabbage, garlic cloves, and onion. Boil uncovered for one hour to emulsify the soup.
Prepare Tare: Combine water, soy sauce, sake, mirin, optional shrimp dashi powder, umami extract, and salt in a pot. Heat until just before simmering, then remove from heat.
Assemble Ramen: Reheat soup, blend with an immersion blender for creaminess. Cook noodles, add tare and lard to a bowl, pour soup over, and add toppings like chashu, menma, kikurage, and green onions.