The were a pair of armored cruisers built for the Imperial Japanese Navy (IJN) in the late 1890s. As Japan lacked the industrial capacity to build such warships herself, the ships were built in Britain. They were part of the "Six-Six Fleet" expansion program that began after the defeat of China during the First Sino-Japanese War of 1894–95. Between them, the sister ships participated in all four main naval battles of the Russo-Japanese War of 1904–05—the Battle of Port Arthur, the Battle off Ulsan, the Battle of the Yellow Sea, and the Battle of Tsushima—but played a much more minor role in World War I. Asama ran aground while searching for German commerce raiders in early 1915 and was under repair for the next two years. Tokiwa participated in the Battle of Tsingtao (1914) and also searched for commerce raiders. Both ships made training cruises during the war and continued to do so after 1918.
Asama continued to make training cruises until she ran aground again in 1935, after which she became a stationary training ship for the rest of her career. Tokiwa, converted into a minelayer in 1922–24, was placed in reserve in 1927 after an accidental explosion of several mines damaged her. The ship became a training minelayer in 1940. During the Pacific War of 1941-1945, Tokiwa participated in the occupation of the Gilbert Islands (1941) and Rabaul and Kavieng (1942) in New Guinea. Damaged by American aircraft shortly afterwards, the ship was forced to return to Japan for repairs. Tokiwa laid minefields during 1944–45 until she was twice damaged by mines in 1945. Shortly before the end of the war, American aircraft inflicted heavy damage on the ship and her crew had to beach her. Tokiwa was salvaged in 1947 and subsequently broken up for scrap. Asama survived the war intact and was scrapped in 1946–47.
Background and design
The 1896 Naval Expansion Plan was made after the First Sino-Japanese War of 1894–95 and included four armored cruisers in addition to four more battleships, all of which had to be ordered from foreign shipyards as Japan lacked the capability to build them itself. Further consideration of the Russian building program caused the IJN to believe that the battleships ordered under the original plan would not be sufficient to counter the Imperial Russian Navy. Budgetary limitations prevented ordering more battleships and the IJN decided to expand the number of more affordable armored cruisers to be ordered from four to six ships. The revised plan is commonly known as the "Six-Six Fleet". These ships were purchased using the £30,000,000 indemnity paid by China after losing the First Sino-Japanese War. Unlike most of their contemporaries which were designed for commerce raiding or to defend colonies and trade routes, these cruisers was intended as fleet scouts and to be employed in the battleline.
In June 1896, Sir Andrew Noble, then in Japan, telegraphed Armstrong Whitworth to lay down two stock cruisers. Work then began on a preliminary design based on an improved version of the earlier . Several iterations of the design were made before the IJN approved the final design on 21 August. This was over larger, more heavily armed, and slightly faster the Chilean armored cruiser. The first ship of the class was laid down in October although the Japanese did not order the ships until 6 July 1897.
Description
The ships were long overall and between perpendiculars. They had a beam of and had an average draft of . The sisters displaced at normal load and at deep load. The ships had metacentric heights of . Their crew consisted of 676 officers and enlisted men.
The Asama-class ships had two 4-cylinder vertical triple-expansion steam engines, built by Humphrys, Tennant, each driving a single propeller shaft. Steam for the engines was provided by a dozen cylindrical boilers and the engines were rated at a total of . The ships had a designed speed of and exceeded that speed during their sea trials, reaching from . They carried up to of coal and could steam for at a speed of .