What could be more Japanese than rice? Without the pearly white grain there would be no mochi (rice cakes) at New Year's or sake at shrines, no sushi, no lunchtime onigiri (rice balls), no verdant paddies to mark summer in the countryside.

But Emiko Ohnuki-Tierney, the author of "Rice as Self: Japanese Identities through Time" (Princeton University Press; 1993), warns against simply labeling Japan as being a "rice culture."

Without doubt, rice has a long and complex history in Japan. Archeologists believe visitors from the Asian mainland introduced paddy cultivation to the southern island of Kyushu about 3,000 years ago. From there, as the necessary know-how gradually spread northward, swamps were turned into fields and hunter-gatherers into farmers. Rice soon took on a more symbolic role as well.

"Wet-rice agriculture became the bedrock of the politically powerful, including the ancestors of the Imperial family. It was the basis of their subsistence and political economy. It even entered into the cosmology," said Ohnuki-Tierney — an anthropologist at the University of Wisconsin — in a recent telephone interview.

Key Imperial rituals all centered on the cycle of rice planting and harvest, she said, and rice was the main food used for offerings to the deities. Indeed, it still shows up in the form of mochi (rice cakes) at New Year's and bottles of sake left outside shrines. Meanwhile, as early as the medieval Kamakura Period (1192-1333), the grain was also used as a tax.

Through much of Japan's history, though, rice could be grown only in certain parts of the country. Mountain-dwellers, for instance, ate millet, wheat and other grains until engineering technology advanced enough to let them build elaborate waterworks; far-northern regions had to wait until the late 1800s before cold-hardy rice varieties were developed.

In fact, many scholars believe that a significant portion of the population did not eat rice on a daily basis until the Edo Period (1603-1867) when the country was ruled by a succession of shoguns. Yet farmers who didn't grow rice — and workers who didn't farm at all — were often squeezed out of political and historical representations of the country, said Ohnuki-Tierney.

"The power of the rice ideology meant that non-agrarian populations were written off from history. To say that Japan is a rice culture is to deny the presence of others," she said.

By the 20th century, though, rice was firmly entrenched in the national diet — and with the rise of Japan's militarism, its aggressions in mainland Asia, and then World War II, the humble seed's symbolism took a darker turn.

"Agrarian ideology was ruthlessly used by the military government," wrote Ohnuki-Tierney in her 1993 book. "White rice, that is, domestic rice, was construed to represent the purity of the Japanese self.

"The government told the civilians that the Japanese rice was sent to soldiers at the front to give them energy to win the war; Japan's victory would guarantee abundant domestic rice rather than the 'distasteful' foreign rice whose consumption epitomized the suffering of the Japanese people."

After the war ended, Japan became increasingly affluent and rice consumption soon reached new highs. But as Western foods gained popularity, to many people a rice-heavy diet started to represent a lack of dietary choice, and consumption began a downward slide that's still continuing. Its religious symbolism has faded, too.

"People today hardly know about the role of rice in agrarian cosmology, or that the Emperor had anything to do with rice planting," said Ohnuki-Tierney. But she added that, even today, "It's part of self-identity."