For over a decade Japan has had a growing problem with Russian and Chinese military aircraft approaching Japanese airspace and triggering an interception by Japanese fighters. The number of intrusions kept increasing and Japan tried to adapt by sending up fewer aircraft for each intercept. That was still not sufficient to deal with the problem and it was becoming a very serious problem because Japan was retiring older fighters and introducing F-35s. It was more important to devote flying time to training than responding to every instance of Chinese or Russian warplanes showing up. In early 2020 a new tactic was employed for the next fiscal year (ending in March 2021) and Japan now only sends up fighters if the Chinese or Russian military aircraft were about to enter Japanese airspace. Otherwise, Japan depended on ground-based air surveillance radar and the changing patterns of intrusions over the years to determine which approaching aircraft were a potential threat. This seemed to work, as during the last year fighters had to go up 23 percent less than during 2019, when there were 947 interceptions.
These intrusions have been increasing sharply since 2008. In 2011, the 355 Japanese anti-intrusion sorties were up 17 percent over the previous year, while in 2010, sorties were up 29 percent. They have continued to climb to Cold War levels.
Initially the Japanese launched many aircraft for each intrusion. For example, in 2008 a Russian Tu-95 entered Japanese airspace near an uninhabited island about 600 kilometers south of Tokyo. Although the Russian aircraft was in Japanese airspace for only about three minutes the Japanese launched 22 aircraft to intercept. This force included two AWACs aircraft and twenty fighters. No Russian aircraft entered Japanese airspace without permission again until 2013 and the Russians apologized for that one. But as the intrusions increased, the number of interceptors sent out for each incident decreased but were told to be more aggressive. This got a response from the Chinese, who publicly complained about how Japanese warplanes were turning on their targeting radars when Chinese military aircraft approached Japanese air space during 2016. The Chinese considered this unfriendly and unnecessary. What China did not mention was that Chinese warplanes have been coming close to Japanese airspace about 65 times a month in 2016, which is 76 percent more than in 2015. Another trend was that, while Chinese warplanes are not the only ones coming too close to Japanese air space for the last few years, they have accounted for the majority of intrusions. In 2015 Chinese warplanes were responsible for about two-thirds of the incidents and in 2016 they accounted for an even higher proportion. Most of the remaining intrusions are usually Russian. These intrusions are part propaganda; showing the Chinese people that their Air Force is out there confronting traditional enemies and partly partly needed training. This was quite a threat in itself because until the 1990s China did not believe in lots of air time for its military pilots and their aircraft. There was also a political angle, as in intimidating Japan into allowing China to claim territory currently considered Japanese.
China became the major culprit in 2013 when Chinese intrusions exceeded Russian ones. This has been coming for several years. In 2011 nearly 43 percent of the sorties were for Chinese aircraft. That's almost three times as many Chinese intrusions as in 2010. Russian aerial activity has been declining for years and this is believed due to the difficulty and expense of keeping elderly Russian aircraft operational. Russia cannot afford to replace its Cold War era aircraft, China can and is. Lots of new fighters require lots of new pilots to be trained and flying close enough to Japanese or South Korean air space appears to be another form of pilot training,
This is in sharp contrast to the Russian aircraft, which continue to be a nuisance off the coast Japan but in a much less threatening manner. The Russian aircraft are flying more training missions in the Pacific and the Japanese have come to understand how it is nearly impossible for Russian pilots getting out to sea without showing up on a Japanese radar or coming close to Japanese air space. That’s because there is a lot of Japanese airspace off the east coast of Eurasia, so Russian warplanes out there cannot avoid passing close to Japanese air defense radars. China does not have this problem and are obviously getting close on purpose.
The Japanese believe another one cause for this increased activity was more electronic and maritime patrol aircraft were available to the Chinese who have a desire to gather as much information as possible about their strongest potential foe in the area. But the main reason is the dispute with China over the Senkaku Islands near Okinawa. China and Japan both claim these uninhabited islets, which are 320 kilometers southeast of the Chinese mainland, 167 kilometers northeast of Taiwan, and 426 kilometers southwest of Japan (Okinawa, which China also has claims on). The Senkaku Islands and have a total area of 6.3 square kilometers. Taiwan also claims the Senkakus, which were discovered by Chinese fishermen in the 16th century and taken over by Japan in 1879. They are valuable now because of the 360-kilometer economic zone nations can claim in their coastal waters. This includes fishing and possible underwater oil and gas fields.