Marshal O Chin-u (March 8, 1917 - February 25, 1995) was a soldier and politician of North Korea. He was the Minister of Armed Forces for many years until his death in February 1995. O was the third most powerful person in North Korea, after Kim Il-sung and Kim Jong-il. Very little is known about him except for the fact that he served with Kim Il-sung's partisan unit and eventually rose through the ranks of the North Korean Army. He distinguished himself during the Korean War and was a trusted advisor of the North Korean leader until his death, also being his chief guard in 1945.