was the second vessel in the two-ship of

armoured cruiser The armored cruiser was a type of warship of the late 19th and early 20th centuries. It was designed like other types of cruisers to operate as a long-range, independent warship, capable of defeating any ship apart from a pre-dreadnought battles ...

s in the

Imperial Japanese Navy The Imperial Japanese Navy (IJN; Kyūjitai: Shinjitai: ' 'Navy of the Greater Japanese Empire', or ''Nippon Kaigun'', 'Japanese Navy') was the navy of the Empire of Japan from 1868 to 1945, Potsdam Declaration, when it was dissolved followin ...

. She was named after

Mount Ikoma is a mountain on the border of Nara Prefecture and Osaka Prefecture in Japan. It is the highest peak in the Ikoma Mountains with a height of 642 meters. Mount Ikoma is a part of Kongō-Ikoma-Kisen Quasi-National Park. It is one of the most fam ...

located on the border of

Osaka is a Cities designated by government ordinance of Japan, designated city in the Kansai region of Honshu in Japan. It is the capital of and most populous city in Osaka Prefecture, and the List of cities in Japan, third-most populous city in J ...

and

Nara prefecture is a Prefectures of Japan, prefecture of Japan located in the Kansai region of Honshu. Nara Prefecture has a population of 1,321,805 and has a geographic area of . Nara Prefecture borders Kyoto Prefecture to the north, Osaka Prefecture to the ...

. On 28 August 1912, ''Ikoma'' was re-classified as a

battlecruiser The battlecruiser (also written as battle cruiser or battle-cruiser) was a type of capital ship of the first half of the 20th century. These were similar in displacement, armament and cost to battleships, but differed in form and balance of att ...

.Jentsura, Jung & Mickel, p. 77

Background

Construction of the ''Tsukuba''-class cruisers was ordered under the June 1904 Emergency Fleet Replenishment Budget of the

Russo-Japanese War The Russo-Japanese War (8 February 1904 – 5 September 1905) was fought between the Russian Empire and the Empire of Japan over rival imperial ambitions in Manchuria and the Korean Empire. The major land battles of the war were fought on the ...

, spurred on by the unexpected loss of the

battleship A battleship is a large, heavily naval armour, armored warship with a main battery consisting of large naval gun, guns, designed to serve as a capital ship. From their advent in the late 1880s, battleships were among the largest and most form ...

s and to

naval mine A naval mine is a self-contained explosive weapon placed in water to damage or destroy surface ships or submarines. Similar to anti-personnel mine, anti-personnel and other land mines, and unlike purpose launched naval depth charges, they are ...

s in the early stages of the war.Chesneau, p. 232 These were the first major capital ships to be designed and constructed entirely by Japan in a Japanese shipyard, albeit with imported weaponry and numerous components. However, ''Tsukuba'' and ''Ikoma'' were designed and completed in a very short time, and suffered from numerous technical and design problems, including strength of its hull, stability and mechanical failures. The ship was reclassified as a

in 1912.

Design

The ''Tsukuba''-class design had a conventional

armored cruiser The armored cruiser was a type of warship of the late 19th and early 20th centuries. It was designed like other types of cruisers to operate as a long-range, independent warship, capable of defeating any ship apart from a pre-dreadnought battles ...

hull design, powered by two vertical triple-expansion steam engines, with twenty Miyabara boilers, yielding design speed of and a range of at . During speed trials in Hiroshima Bay prior to commissioning, ''Tsukuba'' attained a top speed of . ''Ikoma'' was one of the first ships in the Japanese navy with boilers capable of burning either

coal Coal is a combustible black or brownish-black sedimentary rock, formed as rock strata called coal seams. Coal is mostly carbon with variable amounts of other Chemical element, elements, chiefly hydrogen, sulfur, oxygen, and nitrogen. Coal i ...

heavy fuel oil Heavy fuel oil (HFO) is a category of fuel oils of a tar-like consistency. Also known as bunker fuel, or residual fuel oil, HFO is the result or remnant from the distillation and cracking process of petroleum. For this reason, HFO contains seve ...

. In terms of armament, the ''Tsukuba'' class was one of the most heavily armed cruisers of its time, with four 12-inch 41st Year Type guns as the

main battery A main battery is the primary weapon or group of weapons around which a warship is designed. As such, a main battery was historically a naval gun or group of guns used in volleys, as in the broadsides of cannon on a ship of the line. Later, th ...

, mounted in twin

gun turret A gun turret (or simply turret) is a mounting platform from which weapons can be fired that affords protection, visibility and ability to turn and aim. A modern gun turret is generally a rotatable weapon mount that houses the crew or mechanis ...

s to the fore and aft, along the centerline of the vessel.

Secondary armament Secondary armaments are smaller, faster-firing weapons that are typically effective at a shorter range than the main battery, main (heavy) weapons on military systems, including battleship- and cruiser-type warships, tanks/armored personnel c ...

consisted of twelve guns and twelve 4.7-inch 41st Year Type guns, and four

QF 3-pounder Hotchkiss The QF 3-pounder Hotchkiss or in French use Canon Hotchkiss à tir rapide de 47 mm were a family of long-lived light naval guns introduced in 1886 to defend against new, small and fast vessels such as torpedo boats and later submarines. T ...

guns.

Service record

''Ikoma'' was

laid down Laying the keel or laying down is the formal recognition of the start of a ship's construction. It is often marked with a ceremony attended by dignitaries from the shipbuilding company and the ultimate owners of the ship. Keel laying is one ...

on 15 March 1905, launched 9 April 1906 and commissioned on 24 March 1908 at

Kure Naval Arsenal was one of four principal naval shipyards owned and operated by the Imperial Japanese Navy. History The Kure Naval District was established at Kure, Hiroshima in 1889, as the second of the naval districts responsible for the defense of the ...

, with Captain Egarashi Yasutaro as her chief equipping officer and first captain. Shortly after commissioning at the

, ''Ikoma'' escorted the

United States Navy The United States Navy (USN) is the naval warfare, maritime military branch, service branch of the United States Department of Defense. It is the world's most powerful navy with the largest Displacement (ship), displacement, at 4.5 millio ...

’s

Great White Fleet The Great White Fleet was the popular nickname for the group of United States Navy battleships that completed a journey around the globe from 16 December 1907, to 22 February 1909, by order of President Foreign policy of the Theodore Roosevelt ...

through Japanese waters on its around-the-world voyage in October 1908. In 1910, ''Ikoma'' was sent on a voyage to

Argentina Argentina, officially the Argentine Republic, is a country in the southern half of South America. It covers an area of , making it the List of South American countries by area, second-largest country in South America after Brazil, the fourt ...

to attend that nation’s independence centennial celebrations. From

Buenos Aires Buenos Aires, controlled by the government of the Autonomous City of Buenos Aires, is the Capital city, capital and largest city of Argentina. It is located on the southwest of the Río de la Plata. Buenos Aires is classified as an Alpha− glob ...

, she continued on across the

Atlantic Ocean The Atlantic Ocean is the second largest of the world's five borders of the oceans, oceanic divisions, with an area of about . It covers approximately 17% of Earth#Surface, Earth's surface and about 24% of its water surface area. During the ...

London London is the Capital city, capital and List of urban areas in the United Kingdom, largest city of both England and the United Kingdom, with a population of in . London metropolitan area, Its wider metropolitan area is the largest in Wester ...

England England is a Countries of the United Kingdom, country that is part of the United Kingdom. It is located on the island of Great Britain, of which it covers about 62%, and List of islands of England, more than 100 smaller adjacent islands. It ...

and to other ports in

Europe Europe is a continent located entirely in the Northern Hemisphere and mostly in the Eastern Hemisphere. It is bordered by the Arctic Ocean to the north, the Atlantic Ocean to the west, the Mediterranean Sea to the south, and Asia to the east ...

and returned to Japan via the

Indian Ocean The Indian Ocean is the third-largest of the world's five oceanic divisions, covering or approximately 20% of the water area of Earth#Surface, Earth's surface. It is bounded by Asia to the north, Africa to the west and Australia (continent), ...

, thus circumnavigating the globe. ''Ikoma'' served in

World War I World War I or the First World War (28 July 1914 – 11 November 1918), also known as the Great War, was a World war, global conflict between two coalitions: the Allies of World War I, Allies (or Entente) and the Central Powers. Fighting to ...

, initially during the blockade of the German port of

Qingdao Qingdao, Mandarin: , (Qingdao Mandarin: t͡ɕʰiŋ˧˩ tɒ˥) is a prefecture-level city in the eastern Shandong Province of China. Located on China's Yellow Sea coast, Qingdao was long an important fortress. In 1897, the city was ceded to G ...

in China during the

siege of Qingdao The siege of Tsingtao (; ; zh, s=青岛战役, t=青島戰役) was the attack on the German port of Qingdao (Tsingtao) from Jiaozhou Bay during World War I by Japan and the United Kingdom. The siege was waged against Imperial Germany between 2 ...

from September 1914 as part of Japan's contribution to the Allied war effort under the

Anglo-Japanese Alliance The was an alliance between the United Kingdom and the Empire of Japan which was effective from 1902 to 1923. The treaty creating the alliance was signed at Lansdowne House in London on 30 January 1902 by British foreign secretary Lord Lans ...

. After the fall of the city, ''Tsukuba'' was sent out as part of the search for the German

East Asia Squadron The German East Asia Squadron () was an Imperial German Navy cruiser squadron which operated mainly in the Pacific Ocean between the mid-1890s until 1914, when it was destroyed at the Battle of the Falkland Islands. It was based at Germany's Ji ...

in the

South Pacific The Pacific Ocean is the largest and deepest of Earth's five Borders of the oceans, oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean, or, depending on the definition, to Antarctica in the south, and is ...

until the destruction of the German squadron in the Battle of the Falklands in December 1914. From 1 November 1914 to 17 January 1915, ''Ikoma'' was based out of

Hong Kong Hong Kong)., Legally Hong Kong, China in international treaties and organizations. is a special administrative region of China. With 7.5 million residents in a territory, Hong Kong is the fourth most densely populated region in the wor ...

Singapore Singapore, officially the Republic of Singapore, is an island country and city-state in Southeast Asia. The country's territory comprises one main island, 63 satellite islands and islets, and one outlying islet. It is about one degree ...

and

Townsville The City of Townsville is a city on the north-eastern coast of Queensland, Australia. With a population of 201,313 as of 2024, it is the largest settlement in North Queensland and Northern Australia (specifically, the parts of Australia north of ...

Australia Australia, officially the Commonwealth of Australia, is a country comprising mainland Australia, the mainland of the Australia (continent), Australian continent, the island of Tasmania and list of islands of Australia, numerous smaller isl ...

, protecting British colonies and shipping from German commerce raiders. On 4 December 1915, ''Ikoma'' was in a fleet review off of

Yokohama is the List of cities in Japan, second-largest city in Japan by population as well as by area, and the country's most populous Municipalities of Japan, municipality. It is the capital and most populous city in Kanagawa Prefecture, with a popu ...

, attended by

Emperor Taishō , posthumously honored as , was the 123rd emperor of Japan according to the traditional order of succession, reigning from 1912 until his death in 1926. His reign, known as the Taishō era, was characterized by a liberal and democratic shift in ...

in which 124 ships participated. A similar fleet review was held again off Yokohama on 25 October 1916. ''Ikoma'' remained in Japanese home waters in 1916 and 1917. ''Ikoma'' was a victim of the Washington Naval Agreement of 1922 and was scrapped at

Mitsubishi Heavy Industries is a Japanese Multinational corporation, multinational engineering, electrical equipment and electronics corporation headquartered in Tokyo, Japan. MHI is one of the core companies of the Mitsubishi Group and its automobile division is the prede ...

Nagasaki , officially , is the capital and the largest Cities of Japan, city of Nagasaki Prefecture on the island of Kyushu in Japan. Founded by the Portuguese, the port of Portuguese_Nagasaki, Nagasaki became the sole Nanban trade, port used for tr ...

shipyards in compliance with that accord. She was removed from the

navy list A Navy Directory, Navy List or Naval Register is an official list of naval officers, their ranks and seniority, the ships which they command or to which they are appointed, etc., that is published by the government or naval authorities of a co ...

on 20 September 1923.

Notes

References

* * * * {{DEFAULTSORT:Ikoma Tsukuba-class cruisers Ships built by Kure Naval Arsenal 1906 ships World War I cruisers of Japan Cruisers of the Imperial Japanese Navy