Oil is an essential lubricant in your engine. It lets metal press against metal without damage. For example, it lubricates the pistons as they move up and down in the cylinders.
1 By the time of the Japanese surrender in August 1945, Korea was the second-most industrialized nation in Asia after Japan itself.  But the wartime mobilization of 1937-45 had reintroduced harsh measures to Japanese colonial rule, as Koreans were forced to work in Japanese factories and were sent as soldiers to the front.
Seoul has been a major settlement for over 2,000 years, with its foundation dating back to 18 B.C. when Baekje, one of the Three Kingdoms of Korea, established its capital in what is now south-east Seoul. It continued as the capital of Korea during the Joseon Dynasty and the Korean Empire.