The Imperial Japanese Navy developed a number of spin-stabilized rockets during World War II, but only this one ever saw service use. These went to sea in launchers containg 28 rockets with six launchers on most carriers. The rocket had an incendiary shrapnel warhead, somewhat similar in design to the "Sankaidan" Type 3 projectile used for guns, and had a time fuze set to explode the warhead at either 1,000 or 1,500 meters (1,100 or 1,640 yards). They were electrically fired in pairs or automatically in 14-rocket sets, the latter action taking 10 seconds to fire all rockets.

Gun Characteristics

Designation 76.5 mm/115 3rd Year Type (Model 1914) Kihô
Ship Class Used On Many ships from 1910s through 1930s
Date Of Design 1914
Date In Service 1916 (naval version)
Gun Weight 62 lbs. (28.1 kg) unloaded
Gun Length oa 54 in (1.37 m)
Bore Length 29.5 in (0.75 m)
Number Of Grooves 4 LH twist
Length Of Rifling N/A
Chamber Volume N/A
Rate Of Fire 400 to 500 rpm


Designation 12 cm (4.7") AA Rocket
Ship Class Used On Carriers
Date Of Design 1944
Date In Service 1944
Firing Rails 42.65 in (1.083 m)
Warhead Weight N/A
Maximum Velocity 656 fps (200 mps)
Rate Of Fire 14 rockets in 10 seconds

Reloading was by hand.


Elevation Distance
Range with time fuzes 1,100 or 1,640 yards (1,000 or 1,500 m) 1
Maximum Range
5,250 yards (4,800 m)
Maximium Height at 80 degrees about 7,545 feet (2,300 m)

Propellant burnt for 1.6 seconds.

  • ^Time fuzes were set to either 5.5 seconds or 8.5 seconds.

Mount/Turret Data

Designation 28-rocket launchers

Most Carriers (6) and Shinano (12) 1a: Type 5 (1945) 2a
Weight 3,521 lbs. (1,597 kg)
Elevation +5 / +80 degrees
Elevation Rate 18 degees per second
Train N/A
Train Rate 22 degrees per second

This rocket or a similar one with an HE warhead was also carried by some explosive motor boats fitted with a simple launching trough.

  • ^These launchers were not installed on Shinano before her loss.
  • ^These mountings were adapted from the 25 mm AA triple gun mounting and could be controlled by Ward-Leonard RPC or by two men in protected cabs. The launcher resembled a large box which consisted of four rows of seven rockets each.


Data from:

  • "Naval Weapons of World War Two" by John Campbell
  • "The 12 cm Multiple Rocket Launcher of the Imperial Japanese Navy" article by Hans Lengerer and Tomoko Rehm-Takahara in "Warship Volume IX"


  • US Naval Technical Mission to Japan report O-19: Japanese Projectiles General Types

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