In “the Japan-Korea Annexation Treaty” of 1910, the Japanese Empire promised to give special treatment and secure the status of the Korean emperor, the abdicated emperor, the crown prince, crown princess and their descendents, other royal family members, and those who served with distinction. Accordingly, Emperor Sunjong obtained investiture with the title of King Yi of Changdeokgung (palace), former-Emperor Gojong received the title of Abdicated King Yi of Deoksugung (palace), Crown Prince Yi Eun with the title of crown prince, and Yi Gang and Yi Hui, close relatives of the King, were granted with the title of duke. These members of the Yi royal family were granted respectful treatment and special privileges equivalent to those enjoyed by the Japanese royal family.
The Japanese gave respectful treatment to Korea’s former royal family in order to avoid resistance from the Korean people and also to demonstrate the symbolic harmony between Japan and Korea through the royal families. For this same purpose, they arranged a marriage of convenience between the last crown prince of the Great Han Empire, Yi Eun, and Nashimotonomiya Masako (Yi Bangja) of the Japanese royal family. Although Yi Eun was the crown prince, he lived in Japan and was raised as a Japanese soldier. When he frequently visited Korea, the Japanese prepared magnificent welcoming events with the intention of displaying the friendly relationship between Japan and Korea to the Korean people. They also planned the royal couple’s visit to Europe when the League of Nations was convening in Geneva in 1927. In doing so, they aimed to advertise Japan’s successful colonial rule toward an international audience as well within Korea. In short, the Japanese gave privileges to the former royal family of the Great Han Empire, but this was not real power and they were used as a symbol of the harmonious relationship between Japan and Korea.