Kotetsu, Japan's first ironclad warship, as Stonewall c. 1865.
Career
Builder:	L'Arman , Bordeaux, France
Laid down:	1863
Launched:	21 June 1864
Commissioned:	25 October 1864
Acquired by Japan:	3 February 1869
Decommissioned:	28 January 1888
Fate:	Scrapped
General Characteristics
Displacement:	1,358 t
Length:	59 m oa
Beam:	9.6 m
Draught:	14 ft 3 in (4.3 m)
Propulsion:	12,00 hp (895 kW) double reciprocating engine
Fuel:	Coal, 95 tons
Speed:	9 knots (15 km/h)
Complement:	135
Armament:	1 x 300 pdr (136 kg) Garnard, 2 x 70 pdr (32 kg) Armstrong
Armour:	124 to 89 mm (waterline), turrets 124 mm

Kotetsu (Japanese: 甲鉄, literally "Ironclad") was the first ironclad warship of the Imperial Japanese Navy. Built in France in 1864, and acquired from the United States in 1869, she was an ironclad ram warship. She had a decisive role in the Naval Battle of Hakodate in May 1869, which marked the end of the Boshin War, and the complete establishement of the Meiji Restoration.

Origins

Kotetsu was originally CSS Stonewall, built in Bordeaux, France, for the Confederate Navy. The French government prohibited the ship from being sold to the Confederacy, and instead arranged for it to be sold to Denmark under the name Staerkodder. The deal never happened, and the manufacturer of Stonewall eventually secretly resold her to the Confederacy.

The arrival of the "formidable" Stonewall in America was dreaded by the United States, and several ships tried to intercept her, among them the USS Kearsarge and the USS Sacramento.

After an eventful crossing of the Atlantic, she eventually arrived in the United States near the end of the American Civil War, too late to have a significant effect, as by the time of her October 1864 commissioning the Confederacy was in disarray and near defeat, its navy disintegrating, along with most other Confederate institutions.

Japanese career

Kotetsu was supposed to be delivered to the Bakufu in 1868, in order to reinforce the ongoing modernization of its army and navy. US$30,000 had already been paid, and the remaining US$10,000 were to be paid on delivery. When the Boshin War between the Bakufu and pro-Imperial forces broke out however, Western powers took a neutral stance, retrieved any military advisors they had in Japan, and stopped the delivery of military material, including the delivery of Kotetsu to the Bakufu.

Kotetsu was finally delivered to the new Meiji government in February 1869. She was immediately put to use and dispatched with seven other steam warships to the northern island of Hokkaido, to fight the remnant of the Shogun's forces, who were trying to form an independent Ezo Republic there, with the help of French ex-military advisors.

On March 25, 1869, in Miyako Bay, Kotetsu successfully repulsed a surprise night attempt at boarding by the rebel Kaiten , essentially thanks to the presence onboard of Gatling guns.

She then participated in the invasion of Hokkaido and various naval engagements in the Naval Battle of Hakodate.

Kotetsu was renamed Azuma in 1871 and remained in military service until 1888, when she was turned to non-combat harbor service.

Kotetsu was well-armed with casemated rotating turret guns and well-amoured, and considered a "formidable" and "unsinkable" ship in her time. She could sustain direct hits without her armour being pierced, and prevail against any wooden warship.

In effect, Japan was thus equipped with advanced ironclad warships only ten years after the launch of the first ocean-going ironclad warship in history, the French Navy's La Gloire ("Glory", launched in 1859).

References

• "End of the Bakufu and restoration in Hakodate" 函館の幕末・維新 (Japanese) ISBN 4120016994