The South Manchuria Railway Company (SMRC) produced a large variety of maps that charted their railroad holdings, tracked agricultural and industrial production, and served the needs of government intelligence. To search for maps produced by SMRC, do an advanced search for "Minami Manshū tetsudō kabushiki kaisha" and limit the search to type of material: map. These and other cartographic materials can be requested for viewing in the Geography and Maps Reading Room at the Library of Congress.
In addition to maps published by SMRC, the Library holds a large amount of cartographic materials related to Manchuria published by the imperial Japanese army and the government of Manchoukuo, as well as those produced in China, Russia, and other countries. The primary subject heading for Manchuria-related maps is "Manchuria (China) Maps".
For a broader, more comprehensive list of subject headings related to maps of Manchuria, do a browse search for subjects containing "Manchuria maps", as in the example below.