Sure, to pack your next al-fresco lunch you could turn to paper or plastic — and risk the leaks and messes when the apple mushes into the sandwich and the chips fall to pieces.

Or you could picnic in a more stylish, efficient, artful way. Take a cue from the Japanese and assemble a bento box. The Asian lunch boxes are designed like curio cases, with subdivided or stacked sections that hold various mini-dishes.

A bento box gives food some boundaries — an appreciated approach, especially when fresh apricots and salmon dripping in lime-soy sauce are next-door neighbors.

"A paper sack is so anticlimactic," says Yukari Pratt, a food writer recently based in Tokyo. "In a bento box, everything is protected. Each thing has its own place."

Yet bento boxes are more than just a clever way to segregate the sauced items from the dry, the hot from the cold. They are exemplars of the Japanese concept of "mingei," the marriage of form and function. And for those determined to eat a rainbow of foods, squeeze in their five-a-day or control their portions, the boxes can double as important nutritional tools.

"When you look at the bento box, nine times out of 10 you know that you are getting a balanced, nutritional meal," says Pratt, 40, who prepared her own bento boxes for lunch when she worked at the Takashimaya department store in Tokyo a few years ago. "But it is also aesthetic."

The items displayed in a bento box follow a formula, albeit a creative one. The arrangement usually includes a heap of rice accompanied by a selection of vegetables, meat, fish or eggs. Each prepared food inhabits its own compartment, though sometimes the rice might cohabit with others. (The main dishes and rice go in the larger sections; side dishes are placed in the smaller spaces.)

To ensure a healthful balance as well as an artist's palette, the boxes should contain at least one dish in each of five color groups: red or orange, yellow, green, white, and black, dark purple or brown. The concept of goshiki, or five colors, is based on traditional principles of Japanese cuisine, some of which are rooted in Buddhism.

Indeed, planning your bento can be like a fun party game, or a kindergarten class: For reddish items, opt for carrots, kabocha (Japanese squash) or pickled apricots; for yellow, consider sweet potato, takuan (pickled radish) and scrambled eggs. Green is easy: broccoli, spinach, green peppers, asparagus. Ditto for white: tofu, rice, radish. Choices for black include Japanese eggplant, sesame seeds or seaweeds such as hijiki or kombu.

"It's also a great way to use up leftovers," suggests Pratt, a graduate of the French Culinary Institute in New York City.

The second rule of bento boxing: Employ a range of cooking techniques, another means of pleasing the taste buds and the calorie counters. Foods should be grilled, fried, simmered, steamed, pickled and/or boiled. For example, a box could include grilled mackerel, fried rice, a boiled egg, a pickled plum and a fresh tangerine for dessert.

"You don't want everything to be fried," Pratt says.

None of this needs to be burdensome. Typical recipes for bento box items call for a handful of ingredients and quick preparation. The sections of the boxes could even be filled with prepared foods sold at supermarkets.

THE UBIQUITOUS BOX

These days, bento (the word roughly translates as a picnic or box lunch) is so pervasive in Japan that you can't ride a train or plane, walk into a workplace cafeteria or pop into a 7-Eleven without seeing the familiar takeout containers. Yet they aren't a modern invention. Bento appeared in its most primitive incarnation in Japan centuries ago, when the country's populace was involved mainly in farming, fishing and fighting — occupations that required a commute. Workers would pack their rice lunches in bamboo, oak or magnolia leaves and eat their meals on-site during a midday break. Eventually the boxes became sturdier, made of wooden materials, wicker or woven willow.

The containers evolved into objects of art and beauty during the decorative Edo period (1603-1868), when quotidian wares once hidden in the cupboard were elevated to coveted showpieces. The boxes seemingly were designed by both painters and poets, with delicate blossoms and ethereal landscapes embellishing the lacquer exteriors. Around that time, new shapes also appeared, such as the hangetsu box, or half-moon, and the tiered Shokado, modeled after the paint boxes used by Shokado Shojo, an Edo-era monk and artist.

The focus of the bento meal also shifted from sustenance to celebration. The boxes were prepared for Buddhist festivals; outdoor sojourns, such as cherry blossom viewing; and theater outings. During kabuki and bunraku (puppet theater) performances, for example, the production would take a break so theatergoers could dine on their makunouchi bento.

The practice still exists today, says Pratt, who during a recent kabuki show in Ginza was surprised to see patrons quietly pull their boxes from under their seats, lay napkins on their laps and eat an intermission meal — without ever standing up. (Those who don't plan ahead can buy one outside from a bento vendor.)

NAME GAME

Bento boxes even have specific names that refer to where they are sold or made: ekiben, for train-station bento; soraben, or sky bento, for in-flight dining; conveni-bento, sold in mini-marts. The flavors and foods also vary according to region (Kyoto is known for tofu, northern Japan for beef) and season (autumnal mushrooms and chestnuts, spring bamboo shoots and ferns).

Meanwhile, those not able to fly 17 hours for lunch can get their bento fix closer to home. Assemble one yourself for a weekday lunch.

As he dined on a veggie bento box recently at a Teaism in Washington, D.C., Shann-jit Singh, 27, remembered the ones he ate as a kid in L.A. and on travels to Japan. "I was fascinated by the sections of the bento box, and that they had all of these different flavors but didn't mix together," said Singh. "It was magical."

No plastic container or paper sack has ever elicited such glee.