Partial four-hour walkouts by each shift are planned for Aug. 19 and 20 and again on Aug. 24 and 25, with the full strike on Aug. 21 accompanied by a rally outside the company's Yangjae-dong headquarters in Seoul. The union had already stepped up pressure before and after the summer break by extending partial stoppages from four hours to six.

The bargaining session on Aug. 18 was the first face-to-face meeting in 41 days and produced no common ground. The union's core demands are the size of the performance bonus, reinstatement of dismissed workers, and an extension of the retirement age. Management has held that the retirement age is bound up with workforce structure across the domestic carmaking industry and cannot be settled in a single company's talks.

The scale of lost output depends on strike hours and line utilisation. Ulsan's plants are divided by model, so a single day of full stoppage translates directly into delayed shipments of specific vehicles. Parts suppliers must adjust delivery schedules day by day when assembly lines halt, so the real burden spreads to first- and second-tier suppliers with a lag.

A fair number of Chinese households in Korea work at parts suppliers around Ulsan, Gyeongju and Yangsan. An assembly strike shows up first as reduced overtime and weekend shifts at those plants, and then as a swing in monthly income. Whether the action lasts days or runs to the end of August will determine how much is felt.

No date has been set for the next round. Both sides say working-level contact can continue during the strike, but observers expect the period after the Aug. 21 rally to be the turning point.