They made desperate efforts to cross the existence of Tangun and Ancient Korea off the history. Tangun is a real man who built Ancient Korea (early 30th century B.C. - 108 B.C.), the first state in Korea. From November 1910, they had set their gendarme and police in motion to confiscate more than 200,000 volumes of national classics including history books related to Tangun's Korea from bookshops, local schools annexed to the Confucian shrine and private schools in different parts of Korea and burn them away.

They also organized what was called "Society of Compilation of Korean History Book" in June 1925 to make it compile the Korean history in favor of their military occupation.

"Korean History", fabricated by the Japanese imperialists, wrote that Korea's history was started with Silla, a feudal state that existed from the mid-1st century to 935, and that the history of ancient states before the Three Kingdoms (Koguryo, Paekje and Silla that existed between early 3rd century B.C. and middle 7th century A.D.) was a history of primitive society and legend. They even invented a theory of "Mimana Miyake" meaning "Japan's government agency of Imna" to claim that Japan had put under its control the southern part of Korea for hundreds of years after the 4th century.

To justify such fabricated historical data, the Japanese imperialists distorted a content of the Monument to the Mausoleum of Koguryo's King Kwanggaetho built in 414. In this way, they erased about 3,000-year-long history of the Korean nation from "Korean History" to show as if Korea had been under their colonial rule from the first period of "nation building".

Indeed, Japan is a heinous criminal country that attempted to distort and obliterate even the Korean nation's history.