Shumshu is an anomaly among the Kurils. While its neighbors bristle with volcanic peaks, Shumshu barely rises 189 meters above sea level -- the lowest elevation in the entire chain. The terrain is flat and waterlogged, covered with lakes and marshland, its roughly oval shape spanning 388 square kilometers. The Second Kuril Strait, only 2.5 kilometers wide, separates it from the towering volcanic mass of Paramushir to the southwest. To the north, just 11 kilometers across open water, lies Cape Lopatka at the southern tip of Kamchatka. This proximity to the Russian mainland made Shumshu strategically valuable long before the 20th century -- and eventually made it the most heavily fortified island in the northern Kurils.

The Ainu lived on Shumshu for centuries, subsisting on fish, marine mammals, and birdlife. Because of the island's closeness to Kamchatka, it was the first Kuril island reached by Russian Cossacks, who arrived in the early 1700s. Russian fur traders visited in 1711 and 1713, using Shumshu as a base from which to expand into the rest of the chain and Sakhalin. The island appeared on Japanese maps as early as 1644, claimed by the Matsumae Domain, though Japan exercised no real control. Sovereignty shifted formally to Russia under the 1855 Treaty of Shimoda, then to Japan in 1875 under the Treaty of Saint Petersburg. Japanese settlers established the town of Kataoka on the site of the Ainu village of Mairuppo, built a cannery in 1910, and by the 1940s the civilian population exceeded 2,000.

By the final year of World War II, Shumshu had become a fortress island. The garrison of over 24,500 troops, reinforced by sixty tanks, occupied nine positions centered around Kataoka. Every coastal area suitable for amphibious landing was covered by permanent emplacements and bunkers, all interconnected by underground passages and trenches. Warehouses, power stations, and hospitals were buried deep underground. Miyoshino Airfield, near the island's center, hosted both Army and Navy aircraft -- Nakajima B5N torpedo bombers, Mitsubishi G3M medium bombers, Ki-44 interceptors, and Ki-43 fighters. Kataoka Naval Base, under the command of the Imperial Japanese Navy's 5th Fleet, had oil storage, seaplane facilities, and the neighboring Imaizaki Airfield with its two runways. American forces based in the Aleutians struck these targets with sporadic air raids from 1943 onward.

The Soviet Union had entered the war against Japan on August 8, 1945, and it did not stop when the Emperor broadcast his surrender on August 15. On August 18, Soviet forces landed on Shumshu, beginning a battle that would rage for five days. The Japanese garrison, entrenched in its underground network and supported by tanks, fought fiercely. Combat operations continued until August 23, when the surviving Japanese forces finally surrendered. What followed mirrored events across the Kurils: the Soviets sent Japanese prisoners of war, including most male civilians, to labor camps. Remaining Japanese civilians were forcibly deported. Kataoka was renamed Baikovo. The Soviet Union annexed the island in 1946, and Japan formally relinquished sovereignty under the San Francisco Peace Treaty of 1951.

Today Shumshu has only a seasonal population of roughly 100 people. The underground fortifications remain, their concrete slowly crumbling in the sub-arctic damp. Abandoned Japanese tanks -- relics of the August 1945 battle -- still sit where they were knocked out or abandoned, rusting on the tundra. The lakes and marshes that cover the island's low terrain have reclaimed much of what the military once built. No permanent settlement survives. The island that the Ainu named for its goodness, that Japan fortified against invasion, that the Soviet Union seized in the war's final days, has returned to something close to what it was before any of them arrived: a flat, wet, windswept place at the edge of the world, inhabited mostly by fog and memory.