Let me start by saying I know there are plenty of Japanese people who don't live into their 80s let alone their 90s or 100s. There's more than 120 million people in Japan, so a blanket statement would be foolhardy.
Still, it does appear that some Japanese habits pertaining to food may make people live longer. Japanese people tend not to be grotesquely obese (please, nobody mention sumo wrestlers) and Japanese cuisine features a lot of fish-based dishes.
That said, with so many western/non-Japanese dishes easily available in today's Japan, and with the myriad demands of life affecting everybody, do Japanese people find, perhaps, surprise that there are views outside Japan that Japanese habits contribute to greater longevity?
In full disclosure, I eat natto almost every day, and am convinced as of now that nattokinase will over time degrade arterial plaque.