Article 23 (Restriction on Dismissal, etc.), Labor Standards Act, as last amended by Act No. 12325, Jan. 21, 2014

It is not regulated by law. However, typically underperformance can be a reason for a dismissal. Since a dismissal due to poor performance is very restrictively judged, the evaluation must be done in a fair and objective way and the employee’s ability to work needs to be significantly poor and s/he does not show any progress after training and education from an employer.

*Labor Standards Act

Article 23 (Restriction on Dismissal, etc.)(1) An employer shall not, without justifiable cause, dismiss, lay off, suspend, or transfer a worker, reduce his/her wages, or take other punitive measures (hereinafter referred to as "unfair dismissal, etc.") against him/her.

(2) An employer shall not dismiss a worker during a period of suspension of work for medical treatment of an occupational injury or disease and within 30 days immediately thereafter, and any woman before and after childbirth shall not be dismissed during a period of suspension of work as prescribed by this Act and for 30 days immediately thereafter: Provided, That this shall not apply where the employer has paid a lump sum compensation as provided for under Article 84 or where the employer may not continue to conduct his/her business.