The Japanese Antarctic Expedition of 1910–12, in the ship Kainan Maru, was the first such expedition by a non-European nation. It was concurrent with two major Antarctic endeavours led respectively by Roald Amundsen and Robert Falcon Scott, and has been relatively overlooked in polar history. After failing to land in its first season, the Japanese expedition's original aim of reaching the South Pole was replaced by less ambitious objectives, and after a more successful second season it returned safely to Japan, without injury or loss of life.

The brainchild of an army reserve lieutenant, Nobu Shirase, the expedition was privately funded. It left Japan in November 1910, and after its first season's failure was forced to spend the winter of 1911 in Australia. In its second Antarctic season, 1911–12, it made no major scientific or geographical discoveries, but could claim some significant achievements. These included the first landing on the coast of King Edward VII Land, the fastest recorded sledging journey, and the most easterly point along the Antarctic coast, to that date, reached by a ship. It also became only the fourth team to travel beyond the 80°S mark.

On their return, Shirase and his team were greeted as heroes, but interest swiftly died, and Shirase was burdened with expedition debts that took years to clear. Outside Japan, the expedition was generally dismissed, or ignored altogether. Only many years after Shirase's death in obscurity, in 1946, did the Japanese begin to honour him and his achievements. The availability since 2011 of an English translation of Shirase's account has revealed the story of the expedition to a wider audience. The first Japanese expedition is further commemorated in the names of several geographical features in Antarctica.

Japan's slow emergence from isolation, following the fall of the Tokugawa shogunate in 1868, kept it largely aloof from the growing international interest in polar exploration that escalated in the late 19th and early 20th centuries. However, the idea intrigued and became a private passion for an army officer, Lieutenant Nobu Shirase, who, inspired by the tales that reached him of European explorers such as Franklin, nursed a desire to emulate his heroes and explore the Arctic. In 1893, by way of preparation, Shirase joined an exploration party to the Chishima Islands, led by Meiji Gohji. This expedition turned into a disaster, from which Shirase emerged in 1895 as one of few survivors, most of the party having succumbed to privation or scurvy. The harshness of these experiences did not diminish his Arctic ambitions. He dreamt of conquering the North Pole until, in 1909, he learned that two American rivals, Frederick Cook and Robert Peary, were each claiming, separately, to have reached the Pole. Undaunted, Shirase then changed his plans; he would go south instead, and aim for the still unconquered South Pole.

Shirase knew that other nations were developing similar plans, and that if he were to have any hope of success he would have to move quickly. Early in 1910 he presented an outline of his plans to the government, declaring that, within three years, he would raise the Japanese flag at the South Pole. He added that his expedition would also advance the cause of science: "The powers of the world ridicule the Empire of Japan, saying we Japanese are barbarians who are strong and brave in warfare, but cowardly when it comes to the realm of science. For the sake of bushido (honour) we must correct this regrettable situation".

The government's response was lukewarm; it agreed a financial contribution and the possible loan of a ship, but in the event, parliament would not release the funds. The learned societies were uninterested; in their view, Shirase was neither a scholar nor a scientist, and his plans, despite his statements to the contrary, were focused more on adventure than on science. Even the Tokyo Geographical Society refused its backing. Amid public indifference and press derision, Shirase's fortunes turned when he secured the support of Count Okuma, the former prime minister, a figure of great prestige and influence. Okuma formed and presided over the Antarctic Expedition Supporters Association, and the public began to contribute, mainly in small amounts from what Shirase described as the "student class". Shirase also obtained important backing from one of Japan's leading newspapers, the Asahi Shimbun. Still the scientific community remained aloof, and the journal of the Tokyo Geographical Society, while reporting on other countries' expeditions, ignored the Japanese venture entirely.

Hundreds applied to join the expedition, though none with any polar experience and only one, Terutaro Takeda, with any pretensions to a scientific background – he was an ex-schoolteacher who had also served as a professor's assistant. In the absence of a proper scientific team, Shirase had to scale down his scientific programme; he would concentrate on the conquest of the Pole.

Among the personnel selected were two Ainu people from the far northern Japanese islands, chosen for their skills with dogs and sledges. Dogs would be the prime mode of transport in the Antarctic; Shirase's initial preference for Manchurian ponies was impractical, since the expedition's ship, acquired with the assistance of Okuna, was too small to carry horses. This ship was the Hoko Maru, a former fishing industry service boat. At 30.48 m (100 ft) in length and registering 204 GRT, she was much smaller than the other Antarctic ships of the era – less than a third the size of Robert Falcon Scott's Terra Nova. But she was strongly built, with a double layer hull sheathed with iron plating, and extra protection at the stem. She was rigged as a barquentine, and her sailing power was augmented by a small (18 horsepower) auxiliary engine. At the suggestion of Admiral Togo, she was renamed Kainan Maru, meaning "Opener-up of the South", or "Southern Pioneer". The ship was placed under the command of an experienced seafarer, Captain Naokichi Nomura.