Tokyo scrambled fighter jets 810 times in the fiscal year to March, with more than half aimed at Chinese planes, as the Asian powers remain locked in a tense standoff over competing territorial claims, the defence ministry data published Wednesday showed.
Planes were sent up nine times to ward off North Korean jets, it added.
The total number of dispatches was the highest annual number since fiscal 1989, when Japan scrambled jets some 812 times, mostly to deal with Soviet aircraft.
Tokyo responded 415 times against Chinese aircraft in the latest fiscal year, up from 306 times in fiscal 2012 and 156 times in fiscal 2011, reflecting the spike in tensions between Asia's two biggest economies which both claim islands in the East China Sea.
Japanese jets targeted Russian aircraft 359 times in fiscal 2013, up from 248 times a year earlier, the data showed. The neighbours are also embroiled in territorial disputes.
The remainder targeted the North Korean jets and one Taiwanese incursion with the rest unspecified.
"Japanese scrambles were frequently made against surveillance planes from Russia and fighters from China," the ministry said in a statement.
Chinese planes did not violate Japanese airspace in fiscal 2013, but they were "expanding their area of activity", it added.
In the past fiscal year, a pair of Russian bombers briefly entered Japan's airspace.
Chinese government ships and planes have been seen numerous times near the disputed islands since Tokyo nationalised some of them in September 2012, which pushed already shaky relations to their lowest level in years.
The dispute over the islands -- known as Senkaku in Japan and Diaoyu in China -- has fuelled historical animosities tied to Japan's expansionist drive across Asia in the first half of the 20th century.
The tensions have seen Tokyo look to its security alliance with the United States and boost ties with India, as well as Southeast Asian nations locked in their own territorial rows with Beijing over much of the South China Sea.