The genre is Jiro-kei Ramen.
The first Jiro-kei Ramen I ever had in my life and still ranked as one of the best in the world is the "Loud" menu item at this restaurant. The combination of garlic, soup, and thick noodle is especially addictive. The recommended toppings are all the mashi, and the chashu pork is a little tough, so it is recommended to eat it first.
There is also a menu item called "Yarikkosi Niboshi," which is a unique niboshi ramen with a strong taste that is hard to find elsewhere.