Japan has, since WWII maintained only minimal military capability, having been under the umbrella of the United States since that time.
But given the increasing belligerence of North Korea and the 3000 aircraft strong air force, Japan has started to move earnestly in the direction of defending itself.
Japan’s new fighter jet is very powerful, new radar capability, new stealth materials, new and greater weapons systems and more. They are working with U.S. contractors including Northrop Grumman.
This fighter will have capabilities that are not currently available in U.S., Chinese or Russian fighters. But then again, all of these countries have 6th generation fighters on the drawing board. Japan’s may be the first to fly though. Prototype due in 2024.