In October 2016 China publically complained about how Japanese warplanes were turning on their targeting radars when Chinese military aircraft approached Japanese air space. 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 is 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), part training (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) and part politics (intimidating Japan into allowing China to claim territory currently considered Japanese).
Meanwhile interceptions are increasingly common for the Japanese Air Force. In 2013 Japanese aircraft went up over 25 times a month to confront Chinese aircraft (often recon aircraft) coming too close to Japanese air space. Thus 2013 was the first year 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.
Although Russian warplanes continue to be a nuisance off the coast Japan considers Russian activity much less threatening. 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.
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. All this should be measured against Cold War activity, which peaked in 1984 with 944 interception sorties. After the Cold War ended in 1991 (when there were 488 sorties), the number of intrusions fell through the 1990s, but since 2000 have increased.
These intrusions have been increasing sharply since 2008. 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.
The Japanese believe that one cause for this increased activity is more electronic and maritime patrol aircraft are 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 380 kilometer economic zone nations can claim in their coastal waters. This includes fishing and possible underwater oil and gas fields.