In 1910 Japan annexed Korea by force without Korean emperor's consent and against all Korean people's will. Afterwards Japan invaded Manchuria and significant part of China and emerged as a world power. Eventually Japan's aggression reached Pearl Harbor.
Meantime, Japan imposed use of Japanese language in all documents and daily conversations including names of Korean people, lands, and waters. Japan also changed names of all geographical objects (seas, mountains, rivers, etc.) to Japanese names. That's how the name of the sea in the title of this petition appeared as Sea of Japan despite that Korea had been using East Sea (Donghae in Korean) for thousands of years.
Japanese aggression must be stopped, their wrongdoing must be corrected, and their injustice remedied.