Japan and South Korea need to get to fucking or they need to become more open and attractive to immigration to stave off population shortfalls. There’s shitloads of south and central Americans looking for stable nations to call home, same with Africans, Middle Easterners, and south Asians, these folks are willing to serve in their militaries, contribute to their economies, and they bring fresh blood and ideas to cultures and industries. There’s also a whole lot of other westerners who are super into Asia in general but especially Japan and would move there in a heartbeat for the right incentives.