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.
(on Archives.gov) This armistice signed on July 27, 1953, formally ended the war in Korea. North and South Korea remain separate and occupy almost the same territory they had when the war began. The Korean War, which began on June 25, 1950, when the North Koreans invaded South Korea, officially ended on July 27, 1953.