Izakaya is a Japanese type of tavern or informal pub which food and drinks are served. Izakaya can be found anywhere in Japan. Then, customers sit on chairs in izakaya. However, there are smaller izakaya which customers cannot sit down. There is no chair and therefore they have to stand while they are drinking.
This type of izakaya is called tachinomi or tachinomi-ya. Tachi means standing and nomi means drink. Ya means store. Tachinomi are mostly run by individuals and usually there are only 1-2 staffs.
Usually you have to pay per order as English pub style and credit card is not accepted. Food menus are listed on the whiteboards which are hanged on the walls. Hot and cold foods are available but due to these places are considered to be visited by solo customer, the portion of the food is much smaller than provided by izakaya. Also the prices are much cheaper.