Some of Tokyo's oldest izakaya and tachinomiya (Traditional Japanese bars) can be found under the train tracks at Yurakucho, adjoining the Hibiya subway station.
A few days ago, I wrote about yakitori bars. These are found around this area
Izakaya are the traditional Japanese bars that are popular with Japanese businessmen for an after work drink, in recent years these bars have also gained in popularity with the younger Japanese drinker too. Traditionally to go along with your drinks small partitions of food are served at the Izakaya, giving this establishment a more of a restaurant feel.
Izakaya’s generally feature red paper lanterns at the front of their shop and on the inside menus of short bits of paper with Japanese text on them often decorate the walls. Many Izakaya may have a English menu available or even a menu with pictures of the dishes on them.
The restaurants are divey and tiny, but the food is cheap and delicious! Walk along the tracks until you see a joint with available seats. Order giant beers (Jokki) and yakitori and whatever else looks good.