Yago is used in Kabuki Theater and represents the actors guild name.  The equivalent of a store name for actors. During the feudal times, lower class people were not allowed to hold family names. It was however possible for a merchant or an employee to use his store name as a family name. For example, Chôbê, head clerk at the Yamadaya liquor shop was called Yamadaya Chôbê. The Kabuki actors used family names, like Ichikawa, Nakamura, Onoe, Kataoka or Bandô to name the most famous ones, but it was of course a breach in the law and the yagô was a good way to give the illusion to the Shogunal authorities that actors were not trying to usurp some privileges of the higher classes.

The yagô is very important in Kabuki, more important than the family name of the actor, because it strictly defines the guilds (acting families).
For example the Ichikawa clan is divided in several guilds like Naritaya, Omodakaya or Mikawaya. Without the yagô, there would be no way to understand the close link between the Onoe Kikugorô and Bandô Hikosaburô lines of actors, which share the same guild name (Otowaya). The first ideogram used in a yagô is ya, which means roof/house/shop in Japanese.

In Japanese: 屋号