When then-President Yoon Suk Yeol's martial law decree plunged South Korea into chaos in December, it plummeted sales at Park Myung-Ja's diner in Jechon and became a turning point for many voters in the town.

The 66-year-old chef and restaurant owner is one face of South Korea's North Chungcheong Province, a swing region that has become even more pivotal at a time of deep political polarization in Asia's fourth-largest economy.

"We need to get furthest away from all that martial law drama to get things back to where they were," Park said at her Korean restaurant two hours south of Seoul, adding that liberal candidate "Lee Jae-myung looks all right for that."