It’s become something of a tourist trap, but it’s still a fascinating place to visit, with loads of locals wedging themselves into the tiny restaurants at Omoide Yokocho at Shinjuku.
This site describes what the restaurants are about:
Izakaya (居酒屋) is a Japanese style gastropub where people enjoy drinking and eating. It’s similar to bar/pub but more like a casual restaurant. There are numbers of Izakaya in Japan as many as restaurants, and it’s where people especially gather for after-work or weekends catch-up. Most of Izakaya are very cozy and casual, and some of them are tiny, non-franchised and long-established with very rustic and old-fashion atmosphere.
Omoide Yokocho is a bustling, narrow alley near Shinjuku Station West Exit, and it packs in over 50 small restaurants, with most only able to accomodate 6-8 diners. Here’s some photos from my recent visit: