One day soon—perhaps this week—a skinny, 5'3" Japanese superman will stand on top of the world, the first human being ever to reach the North Pole alone. For Naomi Uemura, 37, the incredible achievement is just another mission accomplished in a career that has made him a national hero in Japan and the greatest solo adventurer since Charles Lindbergh.

In the past 12 years Uemura has made his lonely way to the top of the highest mountain in Europe (Mount Elbrus, 18,481 feet), Africa (Kilimanjaro, 19,340 feet), South America (Aconcagua, 22,835 feet) and North America (McKinley, 20,320 feet). He was also the first Japanese to plant the Rising Sun on Mount Everest, the world's highest peak (29,028 feet), but he is inclined to minimize that conquest because he was a member of a 39-man team. Alone, Uemura has walked the 1,750-mile length of Japan in 53 days, floated 3,728 miles down the Amazon River on a raft in two months ("pure bliss," he says), and, as a warm-up for the North Pole trek, mushed by dog sledge 7,452 miles across the Arctic Circle from Greenland to Alaska in two stages and 363 days. Upon arrival Uemura told an Eskimo, "I've come from Greenland." The man was puzzled. "Where's Greenland?" he asked.

Uemura's 500-mile journey to the pole began on March 5, when he set out with 19 dogs from Cape Columbia on Canada's Ellesmere Island. In 10 days he managed to cover only 10 miles because of ice formations. Then his pace quickened. Airplane drops, costing $10,000 each, have kept him supplied with seal and caribou meat for himself (there is little game in the area) and Ralston Purina chow for his team. (It's one of his sponsors.) Uemura has a battery-powered unit on his dog sledge that transmits his exact location once a minute to NASA's Nimbus-6 satellite orbiting 600 miles overhead. He is in regular radio contact with his base camp on Ellesmere Island. So far he has not called for help, not even when a polar bear raided his camp four days out, eating all the dog food, destroying his tent and ripping up his sleeping bag. Uemura was in it during the attack. When the bear returned the following night, Uemura shot it and fed the carcass to the hungry dogs. Canadian authorities had advised him against eating the meat himself without boiling it thoroughly because of the danger of trichinosis.

Another day six dogs fell through the ice. Uemura, risking his life, managed to drag them out and pat them dry with his layered wool-and-fur mittens before they froze to death. The temperature averages 33" below zero. Four of the dogs proved to be fighters and had to be allowed to run free. They returned to the team each night to be fed. Earlier this month 11 new dogs were airlifted in and 13, including two newborn puppies, were evacuated. The airlifts are troublesome: When a plane is unable to land on skis, the supplies are parachuted in and Uemura must chase around and retrieve them.

Because of the cold, Uemura tucks his radio batteries into a special pouch under his arm to maintain their charge. Often he has to climb pressure ridges more than 30 feet high. He unloads, backpacks his supplies over the ridge and then pulls the dogs and sledge over. In one stretch these ridges occurred every 55 feet. Water is scarce and must be melted on a kerosene stove; Uemura eats all his food uncooked. Baths are out of the question and even the exposure involved in going to the bathroom is perilous. "I've learned to do it in 10 seconds flat," says Naomi.

Uemura is gathering evidence about air pollution and weather and taking ice and snow samples for the Smithsonian Institution and for research institutes in Japan. Actually, his work has barely begun—he is on a six-month trek and will be turning south across the polar ice cap to Greenland and then down the length of that vast empty land. He expects to arrive at its southern tip in August, after scaling the 9,843-foot Greenland ice plateau. At times he will use ice-sailing techniques to speed him on his way. In northern Greenland he will keep his eye out for evidence of a prehistoric culture. In all, the Uemura expedition will cover 3,700 miles at a cost of $410,000, most of it supplied by Japanese newspapers, corporations and individual donors.

He reports feeling depressed occasionally, but fights the Arctic blues by studying a list of friends printed on a canvas bag at the end of his sledge. "They are not financial backers, just people who wish him well," says Lee Houchins of the Smithsonian, who is working on the polar project. Meanwhile Uemura's wife, Kimiko, waits in Tokyo and prays. A 41-year-old calligrapher, she has spent less than half her four years of marriage with her husband and is resigned. "He is among the most stubborn men on earth," she declares, "and among the most bashful." Uemura himself explains away his enthusiasms by saying, "Out there on the rocks, I feel exceedingly happy."

The sixth and youngest son of a rice farmer, he took up mountain climbing as a student at Meiji University, not with any dreams of glory but with the idea of "improving my skinny appearance." Later he decided that he was "not fit for the social process" of densely populated Japan, and a year after graduation went off to climb his first alp—France's 15,771-foot Mont Blanc. That climb was almost his last when he fell into a deep, snow-covered crevasse, but such narrow escapes only whet his appetite for more. Naomi already has his sights set on the next world to conquer alone, after the Arctic adventure is over. The South Pole, of course.