Just around the corner from Shinjuku station - these are small alleys where you have very local restaurants and bars. Most of the food is skewers. Its also known as "piss alley" - worth a visit - best at night

Moide Yokocho is definitely worth a stroll through even if you don't stop for food or a drink. Just outside Shinjuku Station it is a tiny alley crowded with tiny little Izakaya and bars. It's not all that long so doesn't take too much time to explore but has the best aromas of food cooking over charcoal fires.
It is quite pricey to eat but certainly worth the experience at least once. Not speaking any Japanese I ventured into one of the Izakayas that called out to me, selected half a dozen skewers of different meats and vegetables, sat down at one of the 6 or so seats crammed in beside the bar and cracked open a cold beer. The meat was spectacular and the atmosphere awesome. Chatting to some random guy from Kyrgyzstan on the seat next to me added to the experience, you just don't know who you'll meet.

We walked here from the Hotel Century Southern Tower. We got a bit confused but some locals helped us out. Going back was much quicker!!
The food items really looked good. Nice stop before or after a dinner.