Misoya Hachiro Shoten (味噌屋八郎商店) is an excellent choice for miso ramen in Shinjuku. On top of their rich soup lies a nice layer of mayu (black garlic oil).
Black Garlic Oil Miso Ramen
Misoya Hachiro Shoten is run by the Nantssutei ramen group. This group loves using mayu (black garlic oil) in their ramen. It's kind of their thing.
Naturally, the miso ramen they serve in Shinjuku utilizes the same black garlic oil. It playfully glides on top of a salty, lardy, pork bone rich soup.
You're not exactly looking at a light bowl.
But it's layered with complexity - this includes several types of miso. For toppings, there are big slices of chashu pork and a large bushel of bean sprouts and negi (spring onions).
Feel free to add an egg and enjoy the thick, straight noodles.
Misoya Hachiro Shoten
There are a crazy amount of quality ramen shops in Shinjuku. Unfortunately there aren't many with quality miso ramen. But that's where Misoya Hachiro Shoten comes in.
Besides the standard miso ramen (pictured), they have a spicy miso, tomato miso, curry miso, and a miso tsukemen (dipping ramen).
With any of them, you're guaranteed to leave full and satisfied.