Issued in quadrangles 1° of latitude by 2° of longitude. Relief shown variously by contours, form lines, and shading. Coordinated with Series N503, Central Siberia, and L542, Manchuria; covers territory of U.S.S.R. east of 124° east latitude. Names in Southern Sakhalin romanized in accordance with the Modified Hepburn system. Names given in Japanese also. Each sheet includes "Glossary," "Location diagram," and "Reliability diagram." Each sheet has individual title. Some sheets have through route maps of cities on versos. Accompanied by index map on sheet 27 x 41 cm. Series N504. "Maps in this series are being superseded by new maps published in series 1501" -- (note from index).