The was the externally operating division of the Ministry of the Navy of Japan

Ministry of the Navy of Japan

The was a cabinet-level ministry in the Empire of Japan charged with the administrative affairs of the Imperial Japanese Navy . It existed from 1872 to 1945.-History:...

 responsible for the administration of naval vessel construction. From 1923 onward, it took on the role of a research institution for the research and development of naval technologies and engineering. This included studying and investigating existing western naval technology, developing and overseeing Japan's domestic shipbuilding and arms industries, and training officers to become naval engineers and inspectors. The bureau was dismantled along with the naval ministry in November 1945 after Japan surrendered to the Allies at the end of World War II

World War II

World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...

.

Taishō period weapons

The Department developed various weapons during the Taishō period

Taisho period

The , or Taishō era, is a period in the history of Japan dating from July 30, 1912 to December 25, 1926, coinciding with the reign of the Taishō Emperor. The health of the new emperor was weak, which prompted the shift in political power from the old oligarchic group of elder statesmen to the Diet...

. These were known a "Xth Year Type" weapons, with the year being the year of the Taishō Emperor

Emperor Taishō

The was the 123rd emperor of Japan, according to the traditional order of succession, reigning from 30 July 1912, until his death in 1926.The Emperor’s personal name was . According to Japanese customs, the emperor has no name during his reign and is only called the Emperor...

's reign (dating from 30 July 1912 - 25 December 1926).

This nomenclature followed on from Meiji period

Meiji period

The , also known as the Meiji era, is a Japanese era which extended from September 1868 through July 1912. This period represents the first half of the Empire of Japan.- Meiji Restoration and the emperor :...

 - the Meiji Emperor

Emperor Meiji

The or was the 122nd emperor of Japan according to the traditional order of succession, reigning from 3 February 1867 until his death...

's reign (13 February 1867 - 30 July 1912). Records exist of a "8.0 inch 45 caliber, 41st Year Type" (1908).

3rd Year Type Guns (1914)

45 caliber, 3rd Year Type Gun 50 caliber, I 3rd Year Type Gun 50 caliber, II 3rd Year Type Gun 50 caliber, 3rd Year Type Gun BL 50 caliber, 3rd Year Type Gun

6th Year Type Torpedo (1917)

The 6th Year Type torpedo

Torpedo

The modern torpedo is a self-propelled missile weapon with an explosive warhead, launched above or below the water surface, propelled underwater towards a target, and designed to detonate either on contact with it or in proximity to it.The term torpedo was originally employed for...

• Diameter : 21 inches (533 mm)
• Length : 22 in 5 in (6.83 m)
• Weight :3157 lb (1,432 kg)
• Explosive charge: 761 lb (345.2 kg)
• Range :
  • 7000 m (7,655.3 yd) at 36 kn (19.6 m/s)
  • 10000 m (10,936.1 yd) at 32 kn (17.4 m/s)
  • 15000 m (16,404.2 yd) at 26 kn (14.2 m/s).

It was widely used in surface ships and submarines into World War II

World War II

World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...

:

• Ōtori class torpedo boat
  Otori class torpedo boat
  The were a class of eight 840 ton fast torpedo boats of the Imperial Japanese Navy.-Development:The eight ships were ordered in 1934 and were commissioned between 1936 and 1937...
  
  s
• Type B1 submarines
• Kaidai class submarine
  Kaidai class submarine
  The was a type of 1st class submarine operated by the Imperial Japanese Navy before and during World War II. The type name, was shortened to . All Kaidai class submarines originally had a two digit boat name, from I-51 onwards. On 20 May 1942, all Kaidai submarines added a '1' to their name. For...
  
  s
• Kaichū type submarines
• Momi class destroyer
  Momi class destroyer
  The Momi class destroyers was a class of twenty one 2nd class destroyers of the Imperial Japanese Navy. All were named for plants. Obsolete by the beginning of the Pacific War, the Momi were relegated to mostly secondary roles, with some vessels serving throughout the war as patrol vessels...
  
  s
• Wakatake class destroyer
  Wakatake class destroyer
  The was a class of eight 2nd-class destroyers of the Imperial Japanese Navy.-Background:The medium-sized Wakatake-class destroyers were a follow-on to the Momi class destroyer as part of the Imperial Japanese Navy's 8-6 Fleet Program from fiscal 1921 as a lower cost accompaniment to the larger...
  
  s

8th Year Type Torpedo (1919)

The 8th Year Type torpedo:

• Diameter : 24 inches (610 mm)
• Length : 27 in 7 in (8.41 m)
• Weight : 5207 lb (2,361.9 kg)
• Warhead : 441 lb (200 kg)
• Range :
  • 10000 m (10,936.1 yd) at 38 kn (20.7 m/s)
  • 15000 m (16,404.2 yd) at 32 kn (17.4 m/s)
  • 20000 m (21,872.3 yd) at 28 kn (15.2 m/s).

An advance on its predecessor, it was used in:

• Mutsuki class destroyer
  Mutsuki class destroyer
  The was a class of twelve destroyers of the Imperial Japanese Navy. All were given traditional poetic names of the months of the year by the Lunar calendar or phases of the moon...
  
  s

9th Year Type Mine (1920)

The 9th Year Type mine

Naval mine

A naval mine is a self-contained explosive device placed in water to destroy surface ships or submarines. Unlike depth charges, mines are deposited and left to wait until they are triggered by the approach of, or contact with, an enemy vessel...

 was deployed from various ships.

It was used as a test explosive on the hulk of Japanese battleship Tosa

Japanese battleship Tosa

was a planned battleship of the Imperial Japanese Navy. Designed by Yuzuru Hiraga, she was envisioned as the lead ship of the Tosa class of two ships. The battleships would have been armed with ten guns and bring Japan closer to its goal of an "Eight-four" fleet...

.

11th Year Type Guns (1922)

The 11th Year Type gun

Naval artillery

Naval artillery, or naval riflery, is artillery mounted on a warship for use in naval warfare. Naval artillery has historically been used to engage either other ships, or targets on land; in the latter role it is currently termed naval gunfire fire support...

 (12 cm/45 or 4.7 inch) was used in:

• Ōtori class torpedo boat
  Otori class torpedo boat
  The were a class of eight 840 ton fast torpedo boats of the Imperial Japanese Navy.-Development:The eight ships were ordered in 1934 and were commissioned between 1936 and 1937...
  
  s
• Kaidai class submarine
  Kaidai class submarine
  The was a type of 1st class submarine operated by the Imperial Japanese Navy before and during World War II. The type name, was shortened to . All Kaidai class submarines originally had a two digit boat name, from I-51 onwards. On 20 May 1942, all Kaidai submarines added a '1' to their name. For...
  
  s
• Type B submarines
• Type C submarines

Also, 5.51 inch 40 caliber, 11 th Year Type QF