Please look at the "Sea of Japan", there are islands "Matsu I." (Ulleungdo), "Liancourt Rks." (Liancourt Rocks) and "Oki Is."
Matsu Island (Ulleungdo) was coloured in light green (yellowish green) which directed Korean territory and Liancourt Rocks and Oki Islands were coloured in green which directed that they belonged to Japan.[Click the left map to magnify]
One of the most dignified maps showed that Liancourt Rocks were not Korean territory in 1900. Obviously the people of the world didn't think that Liancourt Rocks belonged to Korea. It automatically denies the theory of pro-Korean scholars that Seokdo in the Korean Edict #41 (1900) was Dokdo (Liancourt Rocks).
The world saw Liancourt Rocks to be present in the Japanese territory, as Watanabe Kouki mentioned "Foreign maps show Hornet Rocks (= Liancourt Rocks) to be Japanese territory" in 1878. http://dokdo-or-takeshima.blogspot.com/2007/06/1877-watanabe-says-liancourt-rocks-is.html
And Meiji Government recognised the situation so they decided to incorporate the rocks after they reconfirmed that there were no traces of occupation by any other countries.
Looking at it impartially, the incorporation was done in accordance with the international laws. As far as Korea has no records to have reached Liancourt Rocks before Japan did, and no records to have owned and controlled the rocks before, it seems that Korea's claim is unreasonable.