All appeals are dismissed.

Costs of appeal shall be borne by each party.

The grounds of appeal are examined (to the extent of supplement in case of supplemental appellate briefs not timely filed).

1. The plaintiffs' grounds of appeal and the defendant's first ground of appeal

(a) A lock-out by an employer under Article 46 of the Trade Union and Labor Relations Adjustment Act may be deemed as a legitimate industrial action by the employer if the lock-out is reasonable in light of the specific circumstances, such as the employer’s attitude and process of negotiation, the purpose and method of industrial action by workers, and the degree of the degree of the shock received by the employer. In such cases, the employer is exempted from the obligation to pay wages to the workers

(1) A lock-out is deemed lawful in cases where a lock-out is deemed to have been changed to an aggressive lock-out beyond the defensive purpose against the workers’ industrial action by continuing to maintain the lock-out even if the workers were to discontinue the industrial action and actually return to their work after a certain point of time, in light of the specific circumstances, including workers’ industrial action, etc. However, in cases where the lock-out is deemed to have been changed to an aggressive lock-out out of the defensive purpose against the workers’ industrial action, the subsequent lock-out loses legitimacy. Thus, an employer cannot be exempt from the obligation to pay for the wages during the pertinent period.

(see Supreme Court Decision 2012Da85335, May 24, 2016). In addition, in order for a trade union to conduct an industrial action, the consent of a majority of the union members is obtained through voting (Article 41(1) of the Trade Union and Labor Relations Adjustment Act). Since a lock-out by an employer is recognized as a means to defend the industrial action of the trade union, the employer’s intent to return to work is insufficient to individually express some of the workers.

They are obliged to return.