Calligraphy by a South Korean independence hero, created while awaiting execution for assassinating a Japanese statesman, is breaking new auction records in Seoul, as the country's ultrarich seek to bring historic artwork home.

Revered in the South for his efforts to defend the country against Japanese encroachment, Ahn Jung-geun is best known for his dramatic, high-stakes assassination of Japan's first prime minister, Ito Hirobumi, in 1909 at a railway station in Harbin.

He was hanged for the killing by Japanese authorities in 1910, just months before Tokyo formally annexed the Korean Peninsula, ushering in a brutal period of occupation that lasted until the end of the Second World War.