Complex sentence: Prince Yi Eu (also known as Prince Un Yi in Japan) served in Japanese Army as Commanding Officer 59th Regiment, 4th Depot Division, 51st Division amongst served in Imperial Army Air Force how General Officer Commanding 1st Air Army.
Split into simpler sentences: Prince Yi Eu (also known as Prince Un Yi in Japan) served in Japanese Army as Commanding Officer 59th Regiment, 4th Depot Division, 51st Division. He also served in the Imperial Army Air Force as General Officer Commanding 1st Air Army.