The Russians tried to slip through the strait undetected, maintaining radio silence and steering clear of shipping lanes. Thick fog in the early hours of May 27 seemed to favor them. Then, at 2:45 a.m., the Japanese auxiliary cruiser Shinano Maru spotted three lights on the distant horizon. They belonged to the Russian hospital ship Orel, which was required by international law to keep its lights burning. The Orel mistook the approaching Japanese vessel for a friendly ship and signaled in Russian code -- gibberish to the Shinano Maru's crew, who peered through the mist and counted the silhouettes of ten additional warships. By 4:55 a.m., Captain Narikawa had radioed Admiral Togo: 'Enemy is in grid 203.' The Russians, intercepting the Japanese transmissions, knew they had been found. Togo received the message ten minutes later and began preparing his fleet. The element of surprise had been lost because of a legal requirement to keep the lights on.

The disparity in the fighting was staggering. Togo held every meaningful advantage -- speed, experience, intelligence of local waters, and battle-hardened crews. Five of the ten admirals in both navies who had combat experience with modern warships served under Togo; the Russian commander, Admiral Rozhestvensky, had none. The Japanese Combined Fleet's battle divisions could maneuver at 15 knots; the Russian column was locked at nine. When the fleets engaged, the result was devastating. Russia lost 21 ships sunk, including most of its battleships. Seven ships were captured. Six were interned in neutral ports. Only three vessels -- two destroyers and a transport -- reached Vladivostok. More than 4,380 Russian sailors were killed and 5,917 captured, including the wounded Rozhestvensky himself. Japanese losses amounted to three torpedo boats sunk, 117 men killed, and 583 wounded.

Among the junior officers serving aboard a Japanese cruiser during the battle was Takano Isoroku, who would later change his name to Yamamoto Isoroku. An accidental explosion of an eight-inch shell in a forward gun tore away two of his fingers. Had he lost a third, he would have been medically discharged from the Imperial Japanese Navy. Instead, he stayed in service, eventually rising to plan the attack on Pearl Harbor and command the Japanese fleet through much of the Second World War. The irony runs deeper: the very victory at Tsushima that kept Yamamoto in uniform also planted the seed of overconfidence that would lead Japan to challenge the United States four decades later. As historian Geoffrey Regan later wrote, Togo's triumph 'created a legend that was to haunt Japan's leaders for forty years.' It had been too easy, and the wrong lessons were drawn.

Tsushima's consequences radiated far beyond the Pacific. The battle proved conclusively that big guns and speed trumped mixed batteries of smaller calibers. Britain's First Sea Lord, Admiral Jackie Fisher, used Captain William Pakenham's firsthand observations from aboard the Japanese battleship Asahi to push through HMS Dreadnought, whose construction began in October 1905 and rendered every existing battleship obsolete overnight. The collapse of Russian naval power freed Britain to concentrate its fleet in European waters, which in turn forced Germany to accelerate its own naval buildup under Tirpitz's Fleet Acts -- three of which passed within six years of Tsushima. The resulting arms race fed directly into the tensions that produced World War I. Meanwhile, the battle's geopolitical symbolism was immense. Mahatma Gandhi, Mustafa Kemal Ataturk, Sun Yat-sen, and Jawaharlal Nehru all later cited Tsushima as proof that a non-European nation could defeat a European power. The strait between Korea and Japan had become, for a day, the fulcrum on which the old world order began to tilt.