Vinylon, also known as Vinalon, is a synthetic fiber produced from polyvinyl alcohol, using anthracite and limestone as raw materials. Vinylon was first developed in 1939 by Ichiro Sakurada, Ri Sung Gi, and H. Kawakami. Production of this fiber was delayed for World War II. The fiber was largely ignored in Korea until Ri defected to North Korea in 1950. Trial production began in 1954 and in 1961 the massive February 8 Vinylon Complex was built in Hamhung. Vinylon's widespread usage in North Korea is often pointed to as an example of success of the juche philosophy, and it is known as the juche fiber.