The situation is quite fucked actually.
1/4 of the japanese population are over 65 years old. Because of high life expectancy this number will grow steadily 3.7 % every year until it reaches 1/3 of the population in 2060. The japanese people are not making enough babies to replace the old generation, so it will eventually end up with less working people. More elderly means more taxes. Japan has the highest public debt in the world. They have a debt double their GDP, around 10 trillion. This is a huge issue since the population is decreasing, it will mean that bigger chunk of the population is much older than the young. And in the end the new working people have to pay taxes for the old, that means more tax burden spread through fewer peoples. Not only that, the japanese economy has been stagnating in the last 10 years. Japan has next to no immigration, which means they don't get enough stimulus in their economy or their population growth. The people now are working very long hours, they barely get any free time, so people tend to not mary or look for a partner. Also, people don't have full-time employment, so people that graduate only works at normal paying jobs, plus the living expenses are high, so people don't feel comfortable to get children in an uncertain environment. Many women feel that they would rather concentrate on their careers, and don't think of settling at all. In japan, more people are buying adult diaper than baby diapers. Their economy is going to end up imploding in the end. What they need is immigration. Since they already have a strict system, then they can already give south koreans and chinese that study there just works after. And also compared to the other western countries, they have the least number of patients every year. So the country suffers from a lack of innovation, this would be fixed if they had more immigration. The current immigrant number is at 1.5%, that means the japanese are 98.5% of the population. That is crazy.
The west doesn't have the same issue, because they have a steady flow of working immigrant that stimulate the economy and create a business. Silicon Valley is around 55 of immigrant background, and the companies created there are changing the world.