In 1904 the main armoured cruiser squadron was based at Vladivostok. Consisting of 4 of the most modern heavy cruisers in the world from here they sallied forth hunting down Japanese shipping whenever they could.
Large, modern and heavily armed & armoured these ships were an impressive element and once Port Arthur fell in early 1905 it became Rozhestvensky's fleet objective to link up with this squadron in order to seek a showdown with the Japanese Combined Fleet under Admiral Heihachiro Togo.
In the pre-dreadnought era it was the armoured cruisers that were the real killers of the battle fleets. Battleships had not yet been able to carry fire control systems that were developed enough to carry the weight of battles on their long range shoulders and it was instead the secondary medium range batteries that were able to strip an enemy ships superstructure to the ribbing and eliminate the enemy vessel as an opponent. The Armoured Cruisers of protagonists fleets didn't mount the heavy guns of the Battleships but more than made up for it with an abundance of these medium batteries.
Vladivostok also had a few tricks up its sleeves during this period though, including a small Submarine Flotilla and a small array of Torpedo Boats and Gunboats for close in defence.