TOKYO -- Does this script sound familiar?

The surprise TV hit of the year is a wacky little cartoon show about a funny middle-class family. The family becomes a national pop-culture phenomenon. Posters, T-shirts and other commercial spinoffs pop up everywhere. After a long battle, the cartoon drama catches the long-running No. 1 show to become the nation's top-rated prime-time program.

That scenario is being played out on both sides of the Pacific this fall as the success of "The Simpsons" is matched here by a spectacularly successful cartoon show called "Chibi Maruko-chan," the mega-hit of the season on Japanese television.

At that point, however, all similarities between the Simpson household and the Sakura family featured in "Chibi Maruko-chan" come to an end.

Where the cartoon Simpsons are sour and cynical, the cartoon Sakuras are sugary sweet. Where the Simpsons mock traditional values, the Sakuras glory in them. If Bart Simpson ever met Maruko Sakura, the round-faced third-grader who is the star of the Japanese cartoon, he would get off a few rude cracks about her serrated bangs and pink cheeks, and she would dissolve into embarrassed blushes.

The ascent of "Chibi Maruko-chan" -- it translates to "Tiny Miss Maruko" -- to the top of the heap in the hugely competitive ratings war here reveals a basic secret about Japan. This mighty economic powerhouse, home of the samurai and the sumo wrestler, is hopelessly addicted to cute.

While "Chibi Maruko-chan" concerns the daily to and fro of a 9-year-old, her friends in the third grade, her sixth-grade sister, her parents and her grandparents, it is just as popular among adults as it is among elementary schoolkids, according to the ratings firm Video Research.

When four twentyish women, all reading Chibi Maruko-chan comic books in a downtown Tokyo restaurant, were asked the other day to explain their passion for the cartoon, they replied nearly in unison: "Kawaiiiiii." In English, that would be "cuuuuuuute."

Advertisers, consequently, are using the cartoon show to sell everything from Barbie-like dolls aimed at preteens to credit cards and cordless phones for young executives. Part of the program's success stems from its theme song, "Odoru Ponpokorin," an infectious little ditty along the lines of "Zip a Dee Doo Dah." Released as a record (with Maruko's picture on the jacket, of course), it has become the third-biggest-selling single in Japanese history.

The tune is ubiquitous here; it is by far the most popular choice in the karaoke, or sing-along, bars where "office ladies" and "salarymen" congregate after work.

In addition to the record, "Chibi Maruko-chan" has spawned a massive spinoff industry.

Sales of the six bound volumes of the comic book featuring Tiny Miss Maruko have gone through the roof. Every store in Japan seems to have set aside a special section for Chibi Maruko-chan plates, pennants, calendars, ashtrays, aprons, candy, games etc. The Tokyo public prosecutor last week held a press conference to announce a raid on a gangster's warehouse full of counterfeit (i.e., non-licensed) Chibi Maruko-chan T-shirts and awnings.

All this fervor comes to a head each Sunday at 6 p.m., when millions of households tune in to the Fuji Television network for Maruko's weekly adventure.

Part of the appeal seems to be that each episode revolves around utterly familiar aspects of Japanese school and family life. The audience sees earthquake evacuation drills, teacher visits to the home, students sweeping the floors in school, family discussions about how to spend the father's biannual bonus and trips to view the spring cherry blossoms and the autumn leaves.

All of this is draped in a thick haze of sentimentality. The days don't always go perfectly for Tiny Miss Maruko, but things always work out to a happy ending, with the star cuddling up to sleep in her father's lap or running off happily with her friends.

In one recent show, Maruko's 12-year-old sister goes into standard preadolescent rapture when she obtains the "sign" -- the English word used here to mean "autograph" -- of a current rock heartthrob. Maruko secretly takes the autograph to show it off in school. Naturally, she loses it along the way, and then spends two horrible days searching for the lost sheet of paper.

Finally, Maruko gets up the courage to confess her crime. Before she can get the words out, though, the older sister announces that she is now rapturously in love with a new rock idol and has no further interest in "that other guy's autograph." End of episode. Cut to theme song.

"Chibi Maruko-chan" went on the air in January and got medium ratings at first. Via word-of-mouth, its popularity has grown gradually. This month it toppled the famous drama series "Two Women of Kyoto" to become Japan's top-rated TV show, scoring a stupendous 37.7 share.

The Tokyo press had a cow, man, over that development, with banner headlines announcing the cartoon's triumph. The next step is a feature-length movie, due out at Christmastime, with promises from the producers that it will show Tiny Miss Maruko, pink cheeks aglow, looking absolutely, totally cute.