When Capt. Alexander Rodionov abandoned the bridge of his sinking imperial Russian battle cruiser 75 years ago, it is unlikely that he could have imagined the storm his departure would cause suddenly today.

Yet, the circumstance of the captain's exit from the Admiral Nakhimov on May 28, 1905, have blown up like a force 10 gale on the already troubled waters of Soviet-Japanese relations, embroiling Moscow and Tokyo in a modern tale of high stakes and high politics on -- or rather, under -- the high seas.

There is no dispute that the vessel, an eight-gun, 7,780-ton steam-powered ship launched in 1885 by the czar's St. Petersburg Naval Yard, was mortally shelled and torpedoed during the Imperial Baltic Fleet's disastrous battle with the Japanese near Tsushima in the Korea Strait May 27, 1905.

But what happened next?

Did Rodinov voluntarily scuttle the ship the next day in time-honored naval tradition to keep it and its mysterious cargo from enemy hands, as the Soviets claim?

Or did the Japanese, who already had sunk or captured nearly two dozen other czarist warships in their stunning victory, also capture the Admiral Nakhimov, as Tokyo claims?

And anyway, today's prudent navigator might easily ask in exasperation, who cares?

Moscow and Tokyo both care, because a Japanese entrepreneur named Ryoichi Sasakawa says he has located the wreck and intends to salvage its famous treasure of gold and precious metals that may be worth millions of dollars.

"Piracy!" cry the Soviets. The ship is rightfully Soviet property even today, they say, because "Admiral Nakhimov sank with St. Andrew flying."

The flag of St. Andrew was the official imperial battle ensign and according to the generally unfathomable laws of the sea, developed over centuries of naval engagements and mariners' woes, a warship that sinks flying its colors remains the property of its nation.

But, said the Japanese last month in an official exchange with the Soviet Embassy in Japan, there is evidence to prove the ship was captured before it sank. This would make it a military prize and strengthen Japanese claims to it.

Nonsense, the Soviets have replied in a recent salvo from Leningrad by the official Tass news agency.

"Before leaving the ship and opening her underwater Kingston valves, the crew destroyed all the secret documents, codes, signal books and duty registers. The crusier was sinking bokw first, falling to starboard. Following naval tradition, the commander was the last to leave the vessel.

"In the Russian newspaper, Novoye Vremya," dated June 27, 1905, according to Tass, Alexander Rodionov made an official statement that "the cruiser went down under the flying St. Andrew."

There is more to this than just the treasure. Entwined in the wreck, like the tentacles of a lurking octopus, are matters of national honor and prestige and even volatile territorial disputes between the Soviet Union and its powerful Asian adversaries, Japan and China.

The cruiser was named after Pavel Nakhimov, a czarist flag officer killed during Russia's heroic defense of Sebastopol in the Crimean War. Nakhimov was raised to superhero status by Stalin in his effort to bolster nationalist spirit during World War II. There is now a Nikhimov naval academy as well as an Order of Nakhimov military decoration.

And in 1972, the Soviets commissioned a new, missle-firing cruiser of 7,600-tons and 34-knot speed of the potent Krests II class and named it after the venerable admiral.

The sinking of the cruiser and her sister ships at Tsushima spelled defeat for the czar in the 1904-05 Russo-Japanese War. He was forced to cede to Japan the southern half of oil-rich Sakhalin Island as part of the settlement worked out by president Theodore Roosevelt at the Portsmouth, N.H., peace conference.

But the Soviets took back the half-island after World War II. Tokyo wants it returned, along with the Kurile Islands, which Moscow is now busily reinforcing to the alarm of the Japanese.

[From Tokyo, United Press International reported that salvagers lowered a giant undersea net around the sunken ship Saturday to keep pirates away.]

[Saskawa, 81, said the treasure ship had attracted "foreign ships" believed to be piloted by potential pirates. He did not elaborate, but he has requested cost estimates for radar to detect submarines and an early morning apparatus to locate pirate ships.]

["I plan to salvage the ship before the seas get rought in the winter," he said.]

[Saskawa has said he is willing to give the treasure to the Soviets if they return the Kurile Islands and the southern half of Sakhalin Island.]

If the Soviets renounce claim to the cruiser, it would set an unhealthly precedent for Moscow in the far more important territorial question.

And the Kremlin cannot budge on that dispute for fear of damaging its longstanding rejection of sweeping Chinese demands that thousands of square miles of territory north of the Amur River seized by the czars in the 19th century be returned to Peking.

In these circumstances, it is virtualy unthinkable that the Kremlin will accept the idea that the warship was captured, or worse, forced to surrender.