Kasuga (春日, Vernal Sun) was the name ship of the Kasuga-class armored cruisers of the Imperial Japanese Navy, built in the first decade of the 20th century by Gio.

The ship played a limited role in World War I and was used to escort Allied convoys and search for German commerce raiders in the Indian Ocean and Australasia.

The Japanese government quickly stepped in and purchased them due to increasing tensions with Russia despite the high price of ¥14,937,390 (£1,530,000) for the two sisters.

[8] The ship's keel was laid down on 10 March 1902 with the temporary name of San Mitra and she was launched on 22 October 1902 and renamed Bernardino Rivadavia by the Argentinians.

[11] Kasuga and Nisshin reached Yokosuka on 16 February just as Japan initiated hostilities with its surprise attack on Port Arthur, and began working up with Japanese crews.

In an effort to block the Russian ships in Port Arthur, Togo ordered a minefield laid at the mouth of the harbor on 12 April and Kasuga and Nisshin were tasked to show themselves "as a demonstration of our power".

[12] Tōgō successfully lured out a portion of the Russian Pacific Squadron, including Vice Admiral Stepan Makarov's flagship, the battleship Petropavlovsk.

[13] Emboldened by his success, Tōgō resumed long-range bombardment missions, making use of the long-range capabilities of Kasuga and Nisshin's guns to blindly bombard Port Arthur on 15 April from Pigeon Bay, on the southwest side of the Liaodong Peninsula, at a range of 9.5 kilometers (5.9 mi).

That same day, off Port Arthur, Kasuga collided in the fog with the protected cruiser Yoshino, which capsized and sank with the loss of 318 officers and enlisted men.

[19] Kasuga and Nisshin participated in the Battle of the Yellow Sea on 10 August, but only played a minor role as they were in the rear of the Japanese battleline.

Due to the limited visibility and heavy smoke during the battle detailed knowledge is not available about her activities during the rest of the day's action.

Heavily outnumbering the Russians, he opted for a long-range engagement to minimize any losses and Kasuga opened fire at the obsolete battleship Imperator Nikolai I at a range of 9,100 meters (10,000 yd).

[30] After the incursion of the German commerce raider SMS Wolf into the Indian Ocean in March 1917, the British Admiralty requested that the Japanese government reinforce its ships already present, there and in Australian waters.

[33] On 13 January 1918, Kasuga ran aground on a sandbank in the Bangka Strait, in the Dutch East Indies, where she was stuck until June, when she could finally be refloated for repairs.

[39] On 15 June 1926, the ship helped to rescue the crew of the freighter SS City of Naples that struck a rock off the coast of Japan and broke up.

Two of her crewmen were later awarded silver medals for gallantry during the rescue by King George V.[40] From 1927 to 1942, Kasuga was used as a training vessel for navigators and engineers.

Kasuga capsized at her mooring at Yokosuka on 18 July 1945 during an air raid by United States Navy aircraft from TF-38.