Most Korean citizens over 18 and under 60 years old have a duty to join the National Pension Service (NPS). Those without an income and payment history are exempt from the national pension until they are 27 years old. However, when they become 27 years old, they are forced to join the NPS and must pay more than 9% of their income. When a citizen over 18 years old earns their first income, they must join the NPS even though they have student or military status. As some Millennials and Generation Z (MZ) started to pay their pension, the NPS is a hot potato among the students and a subject worth attention.
 Korea's national pension system shares various common ground with the Prussian pension system, which dates back to the 19th century. Prussia is noted as one of the first states to set up a public pension system in the year of 1889. The Prussian pension system was rolled out under the leadership of Bismarck, the former Minister for Foreign Affairs of Prussia. The main scope of the Prussian pension system was industrial workers. The government provided retirement benefits to workers who were injured while working. Most workers were required to pay into the pension fund, and with additional contributions from the government, the amount of money needed was covered. When they turned 70, all the workers could then receive a pension. Prussia's pension system was considered a groundbreaking social security program back then. 
 Korea's national pension system supplemented and developed various parts of the Prussian pension system. First, the scope of people who receive and pay the pension was expanded. All Korean citizens who are over 60 years old can receive a pension regardless of their jobs, gender, or native country. Second, the amount of money the pension provides increased significantly compared to the past. Economically and socially challenged in need who are old are now fortunate enough to make a nice living thanks to the national pension. 
 Korea's national pension is an excellent system, but there is one drawback, the national pension got off on the wrong foot. The money people between 18 and 60 years old are paying is given to people who are over 60 years old. When the population growth is large enough, and the number of people between 18 and 60 years old is larger than the number of people who are older than 60 years old, there is no problem at all. However, when the population declines due to the low birth rate, people who pay for the pension must pay a lot more to cover the pension that the elderly should receive. If the number of people paying the pension is less than the number of people receiving the pension, the young must pay a lot more. According to Statistics Korea, Korea's birth rate was under 0.8 in 2022 and is still declining. Soon, Korea's national pension will be stuck in a rut, and experts and the public say the national pension needs to change.
 Under the Ministry of Health and Welfare of South Korea (MOHW), the NPS oversees the national pension and is now trying to solve the problem. Currently, the generation with the largest population pays the national pension, so some money is left. The National Pension Service Investment Management operates a fund of 890 trillion KRW and invests in various fields according to its fund portfolio. They make their own decision about what and when to buy and sell bonds, domestic stocks, foreign stocks, etc. During the COVID-19 period, 2019 to 2022, the NPS sold domestic stock and excelled in increasing the fund money.
 There are pros and cons to NPS's domestic stock selling. The opposite opinion is that the price of domestic stocks temporarily falls. Most experts, the cons, say that local stocks should be gradually converted into overseas stocks as soon as possible. This is because in the future, when pensions are given to a larger portion of the population, the NPS eventually must sell domestic stocks. The fall in domestic stocks at that time will be much steeper than the current gradual decline.
 The national pension's primary purpose is to help people set their retirement and make ends meet even when people get old and do not have an income. The reasonable algorithm for how the national pension should work is 'save money and return the money back,' just like other developed countries. In the case of the United States, there are various kinds of pensions, and citizens can choose what pension to join or not. Some say inflation would lower the price of the pension they saved, but the US solved this problem by not assessing tax on the pension payment.