The contrast says a great deal about the Japanese market-and the U.S.
The two key differences are that Japan's baby boomers are smaller in number, and that they have been much more predictable in their behavior.
As in America, the Japanese postwar baby boom started in 1946. But Japan's birthrate peaked in 1949, and then dropped steadily until 1956.
Even as the boom was fading, it still added quite a few Japanese to the population rolls.
So true Japanese boomers plus those born immediately after them-that is, folks now in their 40s-today account for slightly over 15% of Japan's 125 million population.
NO REAL CULTURE
That's a fairly hefty number. Nonetheless, they are largely taken for granted by marketers because, unlike their American counterparts, they were not rebels.
Largely content to absorb their parents' values, Japan's baby boomers immersed themselves in their jobs.
"We've been accused of having no real culture. Our only goal was rebuilding Japan's economy," says Ryouji Nitta, deputy general manager of Nissan Motor Co. product & technology planning.
Boomers' attitudes toward cars certainly stayed close to their parents'. Growing up in a devastated post-war Japan, boomers didn't always have a car. Therefore, they grew up aspiring to a fancy sedan-and still do.
"The objective was to move up the grades," rising from a Nissan Bluebird, say, to the top-of-the-line President, says Mr. Nitta.
OVER THE HILL
Brand loyalty remains strong, he adds, so that the traditional market-share ranking of Toyota, then Nissan, and so on, is not challenged by the boomers.
As a result, few ads are directed at baby boomers. One, in fact, perceived by several ad executives as aimed at boomers is for the Mercedes C Class. But the campaign features a man in his 60s at the dinner table talking to his grandkids. The message: boomers in Japan are actually over the hill.
In contrast, the generation now in its 30s grew up expecting to have a car and treating it as an appliance. They, not the boomers, are determining where the market is going.
MOVE TO MINIVANS
Japanese in their 30s have led the move out of sedans and into minivans and sport-utility vehicles. They are the first demographic slice where more than 50% of women even have a driver's license, a key precursor to the two-car family.
So it's the younger generation, not boomers, who have broken the old rules and set new ones, displaying the iconoclasm that U.S. boomers showed as early as the days of the Volkswagen ("Think Small") Beetle.
That's why Japan's 18.7 million boomers in their 40s are less interesting to marketers than the 15.6 million Japanese in their 30s.