Below are maps of Korea (朝鮮摠島) and Gangwon Province (江原道) from the Korean atlas "Yojido." Both the full map of Korea and the map of Gangwon Province show the Korean island of "Gansando" (干山島) off the east shore of "Ulleungdo" (鬱陵島). "Gansando" (干山島) was one of the misspellings for "Usando" (于山島). The map is stored HERE in the US Library of Congress.
Notice that the Gangwon Province map shows Ulleungdo kind of hugging Usando, which may have been done to emphasize the fact that Usando was a neighboring island of Ulleungdo. Later maps of Ulleungdo would move Usando to off Ulleungdo's "east" shore, in a position indicating it was Ulleungdo's neighboring island of Jukdo (竹島), which is about 2.2 kilometers off Ulleungdo's east shore.