Look up the Japanese characters for "Izakaya" and head to Shinjuku or Shibuya. You can basically enter any building on the more busy streets and have a bar on every floor. Ask the door staff about food and drinks incuding "nomihoodai" and "tabehoodai" ( "all you can eat/drink" ) possibilities and check if the atmosphere and clientele are of your taste. Izakayas often have very innovative takes on Japanese and other food and serve smaller "O-toshi" ( tapas ) to accompany drinks.

Please note that the "nomihoodai" drinks tend to be of inferior quality compared to the "normal" menu. It's always good to tell the staff if you like dryer ("karaguchi") or more fruity ( "amaguchi" ) ricewine and Shochu.

The "Opera City" complex on the Western outskirts of Shinjuku offers bars with a view and for a lesser cost compared to the main hotels.

The smaller, more intimate bars are often for a specific customer group and do often not welcome strangers, especially if they are not Japanese. Please do not argue too much in this case as you never know if you have just entered some Yakuza relaxation spot.