was an that served as an

armed merchant cruiser An armed merchantman is a merchant ship equipped with guns, usually for defensive purposes, either by design or after the fact. In the days of sail, piracy and privateers, many merchantmen would be routinely armed, especially those engaging in lo ...

in the

Second World War World War II or the Second World War (1 September 1939 – 2 September 1945) was a World war, global conflict between two coalitions: the Allies of World War II, Allies and the Axis powers. World War II by country, Nearly all of the wo ...

. She was launched in 1939 and completed in 1940 for Osaka Shosen Lines. In 1941 she was commissioned into 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 served as a

commerce raider Commerce raiding is a form of naval warfare used to destroy or disrupt logistics of the enemy on the open sea by attacking its merchant shipping, rather than engaging its combatants or enforcing a blockade against them. Privateering is a fo ...

and

submarine tender A submarine tender, in British English a submarine depot ship, is a type of depot ship that supplies and supports submarines. Development Submarines are small compared to most oceangoing vessels, and generally cannot carry large amounts of foo ...

. Two Allied naval ships sank her in a naval engagement in 1942.

Building

''Hōkoku Maru'' was designed as a

cargo liner A cargo liner, also known as a passenger-cargo ship or passenger-cargoman, is a type of merchant ship which carries general cargo and often passengers. They became common just after the middle of the 19th century, and eventually gave way to conta ...

for Shosen Line's scheduled services to

South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a considerably smaller portion in the Northern Hemisphere. It can also be described as the southern Subregion#Americas, subregion o ...

. She 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 ...

at the Tama shipyard in

Okayama Prefecture is a Prefectures of Japan, prefecture of Japan located in the Chūgoku region of Honshu. Okayama Prefecture has a population of 1,826,059 (1 February 2025) and has a geographic area of 7,114 Square kilometre, km2 (2,746 sq mi). Okayama Prefecture ...

on 18 August 1938. She was launched on 5 July 1939 and completed on 22 June 1940.Hackett & Kingsepp Designed as a luxury

ocean liner An ocean liner is a type of passenger ship primarily used for transportation across seas or oceans. Ocean liners may also carry cargo or mail, and may sometimes be used for other purposes (such as for pleasure cruises or as hospital ships). The ...

, she had a luxury suite of rooms called the Nara Suite after the city of that name. However, the Japanese admiralty influenced the design of the ''Hōkoku Maru''-class, to make them suitable for use as

troop ships A troop is a military sub-subunit, originally a small formation of cavalry, subordinate to a Squadron (cavalry), squadron. In many armies a troop is the equivalent element to the infantry section (military unit), section or platoon. Exception ...

. The Japanese government provided large subsidies for such dual-purpose designs from 1936 onwards. ''Hōkoku Maru''s registered length was , her beam was and her depth was . Her

tonnage Tonnage is a measure of the capacity of a ship, and is commonly used to assess fees on commercial shipping. The term derives from the taxation paid on '' tuns'' or casks of wine. In modern maritime usage, "tonnage" specifically refers to a cal ...

s were and . She had two

screws A screw is an externally helical threaded fastener capable of being tightened or released by a twisting force (torque) to the screw head, head. The most common uses of screws are to hold objects together and there are many forms for a variety ...

, each powered by a 12-cylinder, single-acting,

two-stroke diesel engine A two-stroke diesel engine is a diesel engine that uses compression ignition in a two-stroke combustion cycle. It was invented by Hugo Güldner in 1899.Mau (1984) p.7 In compression ignition, air is first compressed and heated; fuel is then in ...

. Between them her two engines were rated at 2,490 NHP,''Lloyd's Register of Shipping'', 1941, HOH–HOK and they gave her a speed of .

Civilian career

''Hōkoku Maru'' was registered in

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 ...

. Her

call sign In broadcasting and radio communications, a call sign (also known as a call name or call letters—and historically as a call signal—or abbreviated as a call) is a unique identifier for a transmitter station. A call sign can be formally as ...

was JCSN. Instead of running between Japan and South America, ''Hōkoku Maru'' mostly operated between

Kobe Kobe ( ; , ), officially , is the capital city of Hyōgo Prefecture, Japan. With a population of around 1.5 million, Kobe is Japan's List of Japanese cities by population, seventh-largest city and the third-largest port city after Port of Toky ...

in Japan and

Dairen Dalian ( ) is a major sub-provincial port city in Liaoning province, People's Republic of China, and is Liaoning's second largest city (after the provincial capital Shenyang) and the third-most populous city of Northeast China (after Shenyang ...

in the Japanese

puppet state A puppet state, puppet régime, puppet government or dummy government is a State (polity), state that is ''de jure'' independent but ''de facto'' completely dependent upon an outside Power (international relations), power and subject to its ord ...

Manchukuo Manchukuo, officially known as the State of Manchuria prior to 1934 and the Empire of Great Manchuria thereafter, was a puppet state of the Empire of Japan in Northeast China that existed from 1932 until its dissolution in 1945. It was ostens ...

, with some calls at Moji,

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 ...

and

Nagoya is the largest city in the Chūbu region of Japan. It is the list of cities in Japan, fourth-most populous city in Japan, with a population of 2.3million in 2020, and the principal city of the Chūkyō metropolitan area, which is the List of ...

. Her only recorded voyage to South America started from Moji on 27 July 1940. She then resumed her route between Dairen and Kobe.

Conversion

On 29 August 1941 the Japanese Navy requisitioned ''Hōkoku Maru''. The

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 ...

shipyard at Kobe armed her with four 15 cm/50 41st Year Type guns, two

QF 12 pounder 12 cwt naval gun The QF 12-pounder 12-cwt gun (Quick-Firing) (abbreviated as Q.F. 12-pdr. 2-cwt. was a common, versatile caliber, calibre naval gun introduced in 1894 and used until the middle of the 20th century.

s, two Type 93 13.2-mm machine guns and two twin-mount

torpedo tube A torpedo tube is a cylindrical device for launching torpedoes. There are two main types of torpedo tube: underwater tubes fitted to submarines and some surface ships, and deck-mounted units (also referred to as torpedo launchers) installed aboa ...

s. In October 1941 she was fitted with 900mm and 1,100mm

searchlight A searchlight (or spotlight) is an apparatus that combines an extremely luminosity, bright source (traditionally a carbon arc lamp) with a mirrored parabolic reflector to project a powerful beam of light of approximately parallel rays in a part ...

s and a boom for handling a

Kawanishi E7K The Kawanishi E7K was a Japanese three-seat reconnaissance seaplane mainly in use during the 1930s. It was allocated the World War II Allied names for Japanese aircraft, reporting name Alf by the Allies of World War II. Design and development In ...

floatplane A floatplane is a type of seaplane with one or more slender floats mounted under the fuselage to provide buoyancy. By contrast, a flying boat uses its fuselage for buoyancy. Either type of seaplane may also have landing gear suitable for land, ...

, with a second aircraft as a spare. Despite her intended role as a commerce raider, little attempt was made to disguise ''Hōkoku Maru'' as a merchant ship. Her guns were fitted with gun-shields and were left in open sight, and she was painted in two-tone naval camouflage.

Naval career

''Hōkoku Maru'' was commissioned into the Japanese Navy on 20 September 1941 under the command of

Captain Captain is a title, an appellative for the commanding officer of a military unit; the supreme leader or highest rank officer of a navy ship, merchant ship, aeroplane, spacecraft, or other vessel; or the commander of a port, fire or police depa ...

Aihara Aritaka. On 15 November 1941 ''Hōkoku Maru'' and her

sister ship A sister ship is a ship of the same Ship class, class or of virtually identical design to another ship. Such vessels share a nearly identical hull and superstructure layout, similar size, and roughly comparable features and equipment. They o ...

, sailed for Jaluit in preparation for the opening of hostilities against the

United States The United States of America (USA), also known as the United States (U.S.) or America, is a country primarily located in North America. It is a federal republic of 50 U.S. state, states and a federal capital district, Washington, D.C. The 48 ...

. On 7 December 1941 the two ships were in the

Tuamotu Archipelago The Tuamotu Archipelago or the Tuamotu Islands (, officially ) are a French Polynesian chain of just under 80 islands and atolls in the southern Pacific Ocean. They constitute the largest chain of atolls in the world, extending (from northwest to ...

at the start of a two-month raiding voyage that sank two Allied

merchant ship A merchant ship, merchant vessel, trading vessel, or merchantman is a watercraft that transports cargo or carries passengers for hire. This is in contrast to pleasure craft, which are used for personal recreation, and naval ships, which are ...

s: ''St Vincent'' off

Pitcairn Island Pitcairn Island is the only inhabited island of the Pitcairn Islands, in the southern Pacific Ocean, of which many inhabitants are descendants of mutineers of HMS ''Bounty''. Geography The island is of volcanic origin, with a rugged cliff ...

and near the

Cook Islands The Cook Islands is an island country in Polynesia, part of Oceania in the South Pacific Ocean. It consists of 15 islands whose total land area is approximately . The Cook Islands' Exclusive Economic Zone (EEZ) covers of ocean. Avarua is its ...

, before returning to Japan in February 1942. In Japan, ''Hōkoku Maru'' was refitted, and was re-armed with 8 x 140mm (5.5 inch) guns. She was also outfitted as a

to support operations by the IJN's 8th Submarine Squadron off

East Africa East Africa, also known as Eastern Africa or the East of Africa, is a region at the eastern edge of the Africa, African continent, distinguished by its unique geographical, historical, and cultural landscape. Defined in varying scopes, the regi ...

. In May 1942, ''Hōkoku Maru'', again with ''Aikoku Maru'', sailed for

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 ...

, thence to 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), ...

. There they captured the Dutch tanker ''Genota'' south of Diego-Suarez,

Madagascar Madagascar, officially the Republic of Madagascar, is an island country that includes the island of Madagascar and numerous smaller peripheral islands. Lying off the southeastern coast of Africa, it is the world's List of islands by area, f ...

, and sank the

British British may refer to: Peoples, culture, and language * British people, nationals or natives of the United Kingdom, British Overseas Territories and Crown Dependencies. * British national identity, the characteristics of British people and culture ...

cargo ship A cargo ship or freighter is a merchant ship that carries cargo, goods, and materials from one port to another. Thousands of cargo carriers ply the world's List of seas, seas and Ocean, oceans each year, handling the bulk of international trade. ...

''Elysia'' south of the

Mozambique Channel The Mozambique Channel (, , ) is an arm of the Indian Ocean located between the Southeast African countries of Madagascar and Mozambique. The channel is about long and across at its narrowest point, and reaches a depth of about off the coa ...

, before re-arming the submarines of the 8th Submarine Squadron off the east coast of

Africa Africa is the world's second-largest and second-most populous continent after Asia. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 20% of Earth's land area and 6% of its total surfac ...

. In July 1942 the two raiders captured the

New Zealand New Zealand () is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and List of islands of New Zealand, over 600 smaller islands. It is the List of isla ...

cargo ship ''Hauraki'', which they sent to Singapore under a

prize crew A prize crew is the selected members of a ship chosen to take over the operations of a captured ship. History Prize crews were required to take their prize to appropriate prize courts, which would determine whether the ship's officers and crew h ...

. Returning to Singapore, ''Hōkoku Maru'' was re-equipped with two

Aichi E13A The Aichi E13A (World War II Allied names for Japanese aircraft, Allied reporting name: "Jake") is a long-range reconnaissance seaplane used by the Imperial Japanese Navy (IJN) from 1941-45. Numerically the most important floatplane of the IJN, i ...

(Allied reporting name "Jake") floatplanes, and an experimental two-tone

dazzle camouflage Dazzle camouflage, also known as razzle dazzle (in the U.S.) or dazzle painting, is a type of ship camouflage that was used extensively in World War I, and to a lesser extent in World War II and afterwards. Credited to the British marine art ...

scheme. In November 1942 ''Hōkoku Maru'', again in company with ''Aikoku Maru'', left Singapore for the Indian Ocean, on what would be her last raiding voyage.

Loss

On 7 November 1942, ''Hōkoku Maru'' and ''Aikoku Maru'' passed through the

Sunda Strait The Sunda Strait () is the strait between the Indonesian islands of Java island, Java and Sumatra. It connects the Java Sea with the Indian Ocean. Etymology The strait takes its name from the Sunda Kingdom, which ruled the western portion of Ja ...

into the Indian Ocean. Four days later, on 11 November 1942, they encountered the Dutch armed tanker , escorted by the

Royal Indian Navy The Royal Indian Navy (RIN) was the naval force of British Raj, British India and the Dominion of India. Along with the Presidency armies, later the British Indian Army, Indian Army, and from 1932 the Royal Indian Air Force, it was one of the ...

corvette A corvette is a small warship. It is traditionally the smallest class of vessel considered to be a proper (or " rated") warship. The warship class above the corvette is that of the frigate, while the class below was historically that of the sloo ...

off the

Cocos (Keeling) Islands The Cocos (Keeling) Islands (), officially the Territory of Cocos (Keeling) Islands (; ), are an Australian external territory in the Indian Ocean, comprising a small archipelago approximately midway between Australia and Sri Lanka and rel ...

. As ''Hōkoku Maru'' engaged, ''Bengal'' and ''Ondina'' returned fire, and a

shell Shell may refer to: Architecture and design * Shell (structure), a thin structure ** Concrete shell, a thin shell of concrete, usually with no interior columns or exterior buttresses Science Biology * Seashell, a hard outer layer of a marine ani ...

, probably from ''Ondina's'' single gun, hit ''Hōkoku Maru's''

starboard Port and starboard are Glossary of nautical terms (M-Z), nautical terms for watercraft and spacecraft, referring respectively to the left and right sides of the vessel, when aboard and facing the Bow (watercraft), bow (front). Vessels with bil ...

torpedo mount, causing an explosion and uncontrollable fire which spread to the aft

magazine A magazine is a periodical literature, periodical publication, print or digital, produced on a regular schedule, that contains any of a variety of subject-oriented textual and visual content (media), content forms. Magazines are generally fin ...

. After a series of explosions, ''Hōkoku Maru'' sank just two hours after the action commenced. ''Aikoku Maru'' rescued 278 of her crew. Both ''Ondina'' and ''Bengal'' escaped.Kindell

References

Bibliography

* }
''Lloyd's Register of Shipping''
(1941) Volume II: Steamers and Motorships of 300 Tons Gross and Over. London,

Lloyd's Register Lloyd's Register Group Limited, trading as Lloyd's Register (LR), is a technical and professional services organisation and a maritime classification society, wholly owned by the Lloyd’s Register Foundation, a UK charity dedicated to research ...

of Shipping, via

Southampton City Council Southampton City Council is the local authority of the city of Southampton in the ceremonial county of Hampshire, England. Southampton has had a council since medieval times, which has been reformed on numerous occasions. Since 1997 the council ...

External links

*Hackett R, Kingsepp S
IJN Hokoku Maru: Tabular Record of Movement
combinedfleet.com; retrieved 13 December 2018 *Kindell Don

Campaign Summaries of World War 2: Indian Ocean & South East Asia, including Burma. Part 1 of 2 – 1939–1942. navalhistory.net; retrieved 13 December 2018 {{DEFAULTSORT:Hokoku Maru Ships built by Mitsui Engineering and Shipbuilding 1940 ships Maritime incidents in November 1942 Auxiliary cruisers of the Imperial Japanese Navy Submarine tenders of the Imperial Japanese Navy Auxiliary ships of the Imperial Japanese Navy World War II shipwrecks in the Indian Ocean