Recommended bowl: Famous Hakata chain

This is the head branch of a well known Hakata tonkotsu chain with over 40 locations worldwide. They serve a standard porky Hakata-style tonkotsu, along with black versions served with mayu (burnt garlic oil). They use two different pots of simmering bones to make the soup — one pot is the prior day's bones simmering, and the other is today's. Pig heads, back bones, and thigh bones used to make the soup. As the pot boils, it is essential to constantly stir and mix the bones — you'll notice a shop staff member doing so every few minutes, always.