The Hyundai Motor branch of the Korea Metal Workers’ Union began four days of walkouts Wednesday, with industrial action scheduled through Tuesday after three previous rounds of partial strikes. Workers on each shift will strike for four hours Wednesday and Thursday, before the walkouts extend to six hours per shift Friday and next Monday. The latest action marks an escalation from the union’s July 29-31 walkouts, when workers stopped work for four hours per shift each day. According to industry sources, Hyundai Motor estimated that the previous three rounds of partial strikes, totaling 60 hours, resulted in production losses of 42,510 vehicles. Hyundai and the union have not held formal wage negotiations for more than a month, since their 15th round of talks on July 8.