In a Sadajiro's book 朝鮮鉱床論 (Chōsen Kōshōron, Ore deposits of Chosen (Korea)) (hereinafter referred to as his original) published in Showa 19 (1944) , dozens of gold, silver, iron, etc. mines are introduced, and readers may want to know the location of each mine from the described place names like 道/郡/面 (Dō/Gun/Men).  However, identifying the location from the written place names is not an easy task. One of the reasons, as the author himself mentions at the beginning, there are no illustrations in the book. Also, although the references are listed for each chapter, the correspondence between the main text and the literature is unclear, and as shown in the table belowmany matters/things change over time , so the place names and administrative divisions written in his original and/or its references may not match with the ones descrived in maps. For example, even though his original says "宣川郡 宣川邑" (Sensen-gun Sensen-yū, Seoncheon-eup in Seoncheon-gun), it had not yet been promoted to an 邑 (Yū, eup) in 1916-1918, when a series of the topographic maps first edition was created, so we need to search for 宣川面 (Sensen-men, Seoncheon-myeon) in the maps.

Things that change over time include:

In order to decipher his original and references and check their authenticity, it is necessary to track these information that changes over time in a cross-sectoral manner , taking into account the time axis.

The terrain itself also changes. Comparing with modern aerial photographs, we can see that flow path of a river that were meandering in the Taisho era topographic maps are now shortcuts due to erosion (or artificially?). There are some other areas that were submerged in huge dam lakes. Furthermore, even topographical maps from the Taisho period can be seen dotted with holes that appear to have been the remains of open-pit gold dust mining, and place names that suggest that the area was once bustling with mining activity.

This map is a part of Topographic Map Kokusan (谷山, こくさん) No. 13 "Seisen" (成川, せいせん) surveyed in Taisho 7 (1918) modified in Showa 11 (1936) , around latitude 39.25°N and longitude 126.21°E. This shows that the west-flowing Futsuryūkō (沸流江, 비류강, Piryu-gang) is still meandering considerably. West of the city Seisen (成川, 성천, Sŏngch'ŏn), a symbol of a boat and a sidewalk are drawn near the point where the flow path make its closest approach each other, and the road continues to the west, so we can imagine that this is a small ferry (the first edition of the topographic map shows that another boat symbol is drawn on the west side of the point). In modern times the river is shortcut from the point to the west.

In addition, a mining site symbol is shown on the south bank across the northeastern hill from the city of 成川. We can see it as the 三川 (みかわ?/さんせん?, Mikawa?/Sansen?) mine, which was introduced in his original.