What is Hakata ramen and what makes it unique?

Hakata ramen is a regional style of ramen that originated in the Hakata district of Fukuoka city. It's famous for its rich and creamy tonkotsu (pork bone) broth, which is made by boiling pork bones for many hours until the collagen and fat have emulsified into a milky, opaque soup. Hakata ramen is typically served with thin, straight noodles that are cooked to a firm texture. One of the unique features of Hakata ramen is the 'kaedama' system, where you can order an extra serving of noodles to add to your remaining broth.