“…Such a trend has been observed in Japan, the first East Asian country experiencing very low fertility, during the last decade when the period TFR rose gradually from a low of 1.25 in 2005 to 1.46 in 2015. An extensive body of literature has studied socioeconomic factors contributing to fertility decline in Korea, such as costs of education, educational expansion, economic recession, labor market conditions, public policies, and a change in women's position, gender roles, values, and attitudes (Anderson and Kohler 2013;Choe and Park 2006;Eun 2007;Jun 2005;Kim 2007;Kim 2005Kim , 2013Kim 2014;Kwon 2007;Ma 2013Ma , 2014Ma , 2016Park, Lee, and Jo 2013;Woo 2012;Yoo 2006Yoo , 2014Kim and Yoo 2016;Tan, Morgan, and Zagheni 2016). However, the nature of ultra-low fertility has not yet been sufficiently explored.…”