The Japanese Commanders, however, were ignorant of the whereabouts of this dangerous force, and a strong squadron was therefore sent into Japan Sea to search it out, and, if possible, destroy it altogether. The fleet dispatched for this purpose consisted of one battleship and six cruisers, with a torpedo-destroyer flotilla. The cruisers, it should be observed, included the newly-acquired _Nisshin_ and _Kasaga_, which had just been fitted up for war. Rear-Admiral Kamimura, Admiral Togo's second in command at Port Arthur, had direction of the operations, no word of which was allowed at the time to leak out through the ordinary channels. A careful patrol was made of the whole of the coast, both of Manchuria and Japan, several days of this close search finally bringing the Japanese squadron to the very mouth of Vladivostock Harbor itself. Considerable excitement was caused in Russia's northern stronghold when, at 8.50 on the morning of March 6th, without any previous warning of the approaching danger, the garrison perceived the hulls of seven great vessels loom upon the horizon to the south of Askold Island. The presence of the enemy so far north was wholly unexpected, and for some time the real character of the advancing squadron was in doubt. But within an hour all speculation was set at rest and the approaching vessels were seen to be flying the Japanese flag. The great size and imposing aspect of the new cruisers led the Russians to take them for battleships, whence they derived the mistaken idea that Admiral Togo was present himself with his main fleet. As a matter of fact, of course, the Japanese Commander-in-Chief, with scarcely diminished forces, was still watching Port Arthur as a cat watches a mouse, and the circumstance that he could without difficulty spare so powerful a squadron for operations in a far distant quarter of the theatre of war was at once a striking demonstration of Japan's naval strength and of the straits to which the Czar's fleet had been reduced. [Sidenote: At the Mouth of the Golden Horn] By noon Admiral Kamimura's ships were half-way between the coast and Askold Island, making straight for Ussuri Bay, which lies to the southeast of Vladivostock. At the southern end of the peninsula on which the town and fortress of Vladivostock stand, and divided from it by a broad channel called the Bosphorus Strait, there is situated the Island of Kazakavitch. The Bosphorus Strait lies in a northwesterly direction, and on the north side of it are two spacious inlets, Patroclus Bay and Sobol Bay. Beyond these again lies the mouth of the Golden Horn, the Harbor of Vladivostock. [Sidenote: Careful Japanese Calculation]