For more than a decade Japan has been moving away from its post-World War II military policy of concentrating on self-defense policies. While the Japanese economy flourished after World War II, the military remained relatively small. Japan depended on the United States to provide sufficient military capabilities to keep Japan safe from increasing military threats from China and North Korea. Over the last few years Japan has adopted a more aggressive defense policy and spent a lot more on weapons and military equipment. Before that Japan used foreign weapons (under license) and Japanese designed ones solely for Japanese forces. None could be exported and this drove up production costs. All that has changed. Japan changed its laws to allow it to export weapons and Japanese defense firms were encouraged to innovate while maintaining the high-quality Japanese weapons they were known for. Japanese defense manufacturers were only able to produce weapons profitably if they could export them and charge competitive prices.
This was made possible by steep increases in defense spending. This began in the 1980s as the Chinese military was modernized and Chinese defense manufacturers were increasing production and quality. Japanese defense spending went from $11 billion in 1982 to $50 billion in 1996. Peak spending was $61 billion in 2011 followed by years of declines or only small increases. Since 2015 the increases have occurred every year and are now going to sharply increase from $52 billion a year to over $300 billion by the end of the decade.
Most of the increased spending will go to missile defense, military aircraft and the navy. Currently the Japanese military forces have about a quarter million personnel. There is no conscription and all personnel are volunteers. There are only 50,000 military reserve personnel. The birth rate has declined to the point where the population is declining. For example, the Japanese population went from 126 million in 2020 to about 125 million now. Japan still has a large economy, the third largest in the world. Now the government plans to spend enough to make potential aggressors think twice before taking on the Japanese military. Equally important is the unprecedented military alliance with South Korea. Together with the United States, these three countries are creating a military alliance to block any Chinese efforts to expand into the Pacific. Cooperation with South Korea is something new because South Korean resentment over Japanese behavior against Koreans during a military occupation during the first half of the 20th century was only recently acknowledged and apologized for by Japan. Now Japan and South Korea face a common enemy, the more powerful and aggressive Chinese forces.
Japan depends on its long military relationship with the United States to make the large Japanese investment in defense work against China. The American Pacific Fleet has most of its ships committed to the assisting allies Japan South Korea, Taiwan, the Philippines and Australia from any Chinese threats. The Japanese fleet is the largest in the region and the South Korea fleet is growing. Japan also has naval and air bases American ships and military aircraft use, especially in wartime. The combination of Japanese, American and South Korea naval and air forces match whatever the Chinese can deploy against them. The large increase in Japanese defense spending is meant to maintain that superiority.