1873 British Nautical Chart of Japan and Korea

The following nautical chart entitled "Preliminary Chart of Japan Nipon, Kiusiu & Sikok and Part of the Korea" was issued by the British Navy's Hydrographic Office in 1873 and was made from British and foreign government surveys done up to 1870. The chart shows Korea's island of Ulleungdo labeled as "Matu sima" with "Dagelet I." in parenthesis. It also shows Liancourt Rocks labeled as "Liancourt Rks.," "Hornet Is.," and "Menelai and Olivutsa." The chart also shows the non-existent island of Argonaut drawn with a dotted line and labeled as "Take sima or Argonaut P.D." The "PD" next to Argonaut means "Position Doubtful."

The reason I am posting the chart  is that it was mentioned in an 1876 letter written by Watanabe Kouki (渡辺洪基), who was Director of the Bureau of Documents in Japan's Ministry of Foreign Affairs at the time. Mr. Watanabe was researching the location of Dagelet Island, which was the Western name for Korea's Ulleungdo Island, and he used this map as an example of Western maps that showed Dagelet Island at the coordinates 37 degrees 25 minutes N. latitude and 130 degrees 56 minutes E. longitude.

In his letter entitled "Second Opinion on Matsushima," Mr. Watanabe referred to the map in the following way:

If we look at Western texts, the British “Imperial Gazetteer” says that Dagelet Island (pronounced as “Dazera”),  or Matsushima, is an island in the Sea of Japan that is situated between the Japanese Archipelago and the Korean Peninsula. Its northwest corner is at 137 degrees (should read “37 degrees”) 25 minutes north latitude and 130 degrees 56 minutes east longitude (Greenwich means). It was named by La Pérouse in 1787. It has a coastline of sheer cliffs and is approximately 9 ri around. It is covered by dense forest up to its highest point.

Also, “Lippincott’s Pronouncing Gazetteer of the World”  says that Dagelet is a small island in the Sea of Japan that is exactly between Japan and Korea. It has a circumference of 8 ri and is positioned at 37 degrees 25 minutes north latitude and 130 degrees 56 minutes east longitude. If you look this up on a map, the location of the island labeled as Dagelet, or Matsushima, on the British Navy’s navigational chart seems to be at the same position as that in both books.

Traditionally, the name "Matsushima," or "Oki's Matsushima," was used by the Japanese to refer to Liancourt Rocks, which Mr. Watanabe believed were Japanese territory, and the name "Takeshima" was traditionally used by the Japanese to refer to Ulleungdo. However, Mr. Watanabe suspected that the name "Matsushima" was now also being used to refer to Ulleungdo, a suspicion the following British navigational chart seems to bear out. Since the name "Takeshima" had always appeared to the west of  "Matsushima" on old Japanese maps, people must have assumed the non-existent island of Argonaut was Takeshima, Korea's Ulleungdo. Therefore, since the real Ulleungdo was now labeled Matsushima, many Japanese and others believed it to be Japanese territory.