List of Japanese World War II navy bombs

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A diagram of a Type 98 No.25 "Land Bomb" showing the typical construction of Japanese Navy land bombs, a thin walled steel cylinder with a nose and tail screwed and welded on.

This is a complete list of all aerial bombs used by the Imperial Japanese Navy during the Second World War.

Types[edit]

The Japanese navy produced a large number of different types of bombs, these were sub-divided into three main categories:

  • Land bombs - for use against land targets. They were normally not produced to a high standard consisting of a simple cylindrical case, riveted or welded to a cast steel nose.
  • Ordinary bombs - for use against ships. They were produced in general purpose and semi-armor piercing types. They were of higher quality and generally had a smooth machined case
  • Special bombs - for various purposes.

Color coding system[edit]

Bomb type/
mark
Marking scheme Alternate marking scheme Purpose
Nose color
/ band color
Body
color
Tail
color
Body band
color
Nose color
/ band color
Body
color
Tail
color
Body band
color
Land Green Grey Green Blue Green / Blue Grey Grey - Land targets.
Ordinary Green Grey Green - Green / Blue Grey Grey - Ship targets.
Dummy Green / Black White White - - Dummy bomb
Practice Green Black White - Green / Black White White - Training.
Training Black overall - - - - Training.
Smoke Green / Black Grey Grey - - - - - For concealing ships.
Mark 1 Green / Yellow Grey Yellow - - - - - Chemical gas bomb.
Mark 2 Blue Grey Blue - Green / Blue Grey Grey - Anti-submarine.
Mark 3 Silver Grey Silver - Green / Silver Grey Red - For air-to-air bombing.
Mark 4 Green / White Grey Red - - - - - Rocket bomb. For dive bombing capital ships.
Mark 5 Green / White Grey Grey - - - - - Armor piercing bomb. For use against capital ships.
Mark 6 Green / Red Grey Red - - - - - Incendiary.
Mark 7 Green / Purple Grey Purple - - - - - Bacillus bomb.
Mark 8 Green / Brown Grey Grey - - - - - Anti-shipping skip bomb
Mark 19 - - - - - - - - Special bomb used by fighters against bomber formations, redesignated as Mark 28
Mark 21 Green / Brown Grey Grey - - - - - Cluster of small bombs
Mark 22 - - - - - - - - Cluster of spike bombs
Mark 23 Green / Brown Grey Grey - - - - - Time delay bomb
Mark 24 - - - - - - - - Cluster of parachute bombs
Mark 25 - - - - - - - - Cluster of wedge bombs
Mark 26 - - - - - - - - Unproduced time bomb design.
Mark 27 Green / Silver Grey/Red - - - - - - Phosphorus rocket bomb for use against bomber formations.
Mark 28 Green / Brown Silver Red - - - - - Rocket type bomb 10 kg high-explosive.
Mark 31 Grey Grey Grey - - - - - Land type bomb. Uses an influence fuze.

Bombs[edit]

Designation Type Weight Content weight Content type [1] Construction Length Suspension lugs Nose Tail Fuze Notes
No.6 Land Bomb (140 lb) 63.5 kg Picric acid or later Type 98 explosive (mod 1) Cast steel Type 2 Model 2 mod 0 or mod 1 Obsolete during the war. Case is similar to the Type 99 No. 6 Mk. 2[2]
Type 97 No.6 Land Bomb 124 lb 50 lb Picric acid or Type 98 explosive Welded and riveted 1/4 inch steel 40 inches Horizontal navy type Cast steel 7⅞ inches long sheet steel A-3(a) Capable of penetrating 200 mm of reinforced concrete [2]
Type 2 No.6 Model 5 Land Bomb 132 lb (approx) Five 7 kg high explosive bombs with bursting charge Sheet 1/16 inch steel 42 inches Horizontal navy type - 16¼ inches A-3 (a) or A-3 (b)
No.25 Land Bomb 550 lb 330 lb Type 98 explosive Welded and riveted 1/4 inch steel 72 inches Horizontal navy type Cast steel 36.5 inch long sheet steel A-3 (a), A-3 (b), C-2 (a), C-1 (a) Designed in 1938, production ceased early in the Second World War [2]
Type 98 No.25 Land Bomb 532 lb 211 lb Picric acid or Type 98 explosive Welded and riveted 1/2 inch steel 72 inches Horizontal navy type Cast steel 32.5 inch long sheet steel A-3 (a), A-3 (b), C-2 (a), C-1 (a) The bomb was used by Japanese forces at the Battle of Midway.[3] Designed in 1937 adopted in 1938. Capable of penetrating 400 mm of reinforced concrete.[2]
No.80 Land Bomb 1,760 lb 842 lb Picric acid or Type 98 explosive Welded and riveted 1/2 inch steel 113 inches Horizontal, two guide studs, and carrying band Cast steel 41 inch long 1/8 inch steel A-1 (c), B-3 (b), A-3 (d) The bomb was used by Japanese forces at the Battle of Midway.[3] The bomb was designed in 1937 and adopted in 1938, and will penetrate 400 mm of reinforced concrete.[2]
Type 99 No.25 Ordinary Bomb 550 lb 132 lb Type 91 explosive (Trinitroanisol) One piece of machine forged 3/4 inch steel 68 inches Horizontal navy type - 28 inch long 1/16 inch steel A-3 (a), A-3 (b), B-2 (a) Designed in 1938 and adopted in 1939, it is capable of penetrating 50 mm of armor.[2]
Type 2 No. 50 Model 1 Ordinary Bomb 1,100 lb 148 lb Cast blocks of Type 98 explosive One piece of machine forged steel 1 to 7.5 inches thick 78 inches Horizontal, two guide studs and suspension band - 39.5 inch long sheet steel A-3 (f), B-2 (a) Teardrop shaped
No.80 Model 1 Ordinary Bomb 1,820 lb 770 lb Type 91 explosive One piece of machine forged steel 0.75 inch thick 111.5 inches Horizontal, two guide studs, and suspension band - 49 inch long 5/32 inch thick steel A-1 (c), A-3 (c), A-3 (d), tail: B-3 (b)
No.3 Model 2 Ordinary Bomb 70 lb  ? Picric acid [4] One piece of machined steel 33 inches Horizontal stud on either side of the body - 13.25 inches A-1 (a), A-3 (a) Teardrop shaped. Obsolete since the early stages of the war.
No.6 Model 2 Ordinary Bomb 139 lb 65 lb Picric acid One piece of machined steel 42.5 inches Horizontal stud on either side of the body - 17 inches A-1 (a), A-3 (a) Teardrop shaped. Production ceased sometime between 1940 and 1941, although they continued to be used.[2]
No.25 Model 2 Ordinary Bomb 557 lb 228 lb Picric acid One piece of machined steel 5/8 inch thick 71.5 inches Horizontal, navy type - 27 inches A-3 (a), B-3 (a) Teardrop shaped. The bomb was used by Japanese forces at the Battle of Midway[3]
No.50 Model 2 Ordinary Bomb 1080 lb 457.5 lb Type 98 explosive One piece of machined steel 4 to 0.5 inches thick 90 inches Horizontal, two guide studs and suspension band - 33 inches A-3 (a), B-3 (a) Teardrop shaped
Type 99 No.6 Mk 2 - 140 lb 85 lb Type 98 explosive Cast nose plug welded to a 3/16 inch thick cylindrical body 42 inches Horizontal, two guide studs and suspension band - 21 inches A-3 (a) A Mod 1 version of the bomb was also produced with a cylindrical steel anti-ricochet attachment spot welded to the nose giving it a blunt profile.
Type 1 No.25 Mk 2 Model 1 - 572 lb 317 lb Type 98 explosive Cast nose welded to a 1/4 inch thick cylindrical body 72 inches Horizontal, two guide studs and suspension band - 21.5 inches followed
by a 15 inch plywood extension
A-3 (a), B-3 (a) A Mod 1 version of the bomb was also produced with a cylindrical steel anti-ricochet attachment spot welded to the nose giving it a blunt profile.
Type 99 No.80 Mk 5 Armor piercing 1,641 lb [5] 66 lb Type 91 explosive Single piece of machined forged steel 4 inches thick at the nose and two at the tail 95.5 inches Two guide studs and suspension band - 43⅜ inches Two B-2 (b) tail fuzes Tear drop shaped bomb, eight recesses around the nose could allow the fitting of a wind shield if used as a projectile. Adopted in 1941, basically a converted 40 cm AP shell, capable of penetrating 150 mm of armor.[2]
Type 2 No.80 Mk 5 Armor piercing 1,760 lb (approx) 100 lb (approx) Type 91 explosive Single piece of machined forged steel - Two B-2 (b) tail fuzes Intended to supersede the Type 99 No.80. Not produced in large numbers. Designed in 1939, and adopted in 1942.[2]
Type 3 No.150 Mk 5 Armor piercing 3,300 lb (approx) 200 lb (approx) Type 91 explosive Single piece of machined forged steel - Two B-2 (b) type tail fuzes Intended to supersede the Type 99 No.80. Not produced in large numbers. Designed in 1942 and tested in 1944, was in experimental production at the end of the war.[2]
Type 3 No.25 Mk 8 model 1 649 lb (approx) 263 lb (approx) Type 97 explosive Cast steel nose, welded to cylindrical body 0.5 inches thick 67 inches Horizontal type navy Cast steel 27⅜ inches long A-3 (a)
Type 3 No.6 Mk 23 model 1 143 lb (approx) 50 lb (approx) Type 98 explosive
or Picric acid
Cast steel nose, welded and riveted to cylindrical body 0.25 inches thick 40.75 inches Normal type navy Cast steel with anti-riccochet cone 18½ inches long C-2 (a)
Type 4 No.25 Mk 29 Air-to-air bomb - - Explosive with white phosphorus filled steel pellets Sheet steel with wooden blocks in the nose - - - - D-2(a) fuze Under development at the end of the war to replace No.25 Mk 3 for use against bomber formations, having a larger explosive charge and less incendiary shrapnel.
Type 3 No.25 Mk 31 Model 1 Airburst 378 lb 175 lb Type 98 explosive Sheet steel cylinder 0.5 inches thick with blunt nose 62 inches Normal navy type Blunt steel with flange 32 inches Type 3 electric firing device B-3(a) Type 3 fuze triggers the bomb at a height of about 7 meters using an electro optical sensor.
Type 3 No.80 Mk 31 Model 1 Airburst 1,584 lb 922 lb Type 98 explosive cast into blocks Sheet steel cylinder 9/16 inches thick with blunt nose 113 inches Two guide studs and a suspension band Blunt steel with flange 41 inches Type 3 electric firing device B-3(b) Type 3 fuze triggers the bomb at a height of about 7 meters using an electro optical sensor.
Type 5 No.25 Mk 33 Airburst - - Explosive with a layer of cylindrical steel fragments - - - Rounded with plummet fuze holder - Plummet electrical fuze with backup Type 15 model 2 fuze The bomb uses four retarding drogue plates that are opened by an atmospheric pressure fuze to slow descent and release the all-ways plummet fuze, which is suspended by a twenty meter silk clad copper to the main bomb. When the plummet fuze touches the ground the bomb is triggered.

[6]

Ordnance used in Pearl Harbor attack. Left: Type 98 #25 land bomb. Middle: Type 91 modification 2 Torpedo. Right: Type 99 #80 Mark 5 High altitude armor piercing bomb.

Rocket bombs[edit]

The Japanese produced a number of bombs with rocket motors installed, intended for air to air use against bomber formations, or as armor piercing weapons. Only two saw service, the Type 3 No.25 Mk 4 armor piercing rocket bomb, and the Type 3 No.6 Mk.27 air-to-air rocket bomb.

Model Weight Description
Type 3 No.25 Mk 4 Mod 1 315 kg Work on this design began in 1935 and production commenced in 1943. 1.9 meters long, the bomb is an armor piercing design, with a thick forged steel nose. The bomb attained a speed of about 100 meters per second when launched. The principal drawback was the small 3.5 kilogram bursting charge.
Type 5 No.1 Mk 9 Mod 1 33 lb An experimental design, intended for use against surfaced submarines. The bomb carried 2.2 pounds of explosives, and had a velocity of about 230 meters per second. Experiments were conducted in June 1944, and it was adopted in 1945. Production had started at the end of the war, but it had not been used. Capable of penetrating up to 25 mm of armor.[2]
Type 3 No.6 Mk 9 185 lb An experimental design, intended for use against landing craft and small ships. The bomb carried 22 pounds of explosives, and had a velocity of about 230 meters per second.
Type 3 No.6 Mk 27 145 lb A anti-aircraft rocket that replaced the Type 99 No.3 Mk.3 in air-to-air bombing. It consisted of a large rocket motor with a 5.5 pound incendiary shrapnel warhead triggered by a clockwork time fuze with an adjustable delay of up to 10 seconds. The rocket had a maximum velocity of around 270 m/s, and the warhead contained 140 iron pellets with white phosphorus embedded in them, these were scattered in a 60 degree cone when the warhead was triggered. The bomb was designed in January 1944 and adopted in February 1945.[2]
Type 3 No.1 Mk 28 20 lb An experimental anti-aircraft rocket with a 1.32 pound high explosive warhead. Experiments were conducted in late 1944. This rocket used 2 kg of propellent and had a maximum velocity of 400 m/s.

Incendiary bombs[edit]

  • Type 99 No.3 Mk 3
  • Type 3 No.6 Mk 3 bomb model 1
  • Type 2 No.25 Mk 3 bomb model 1
  • Type 98 No.7 Mk 6 bomb model 1
  • Type 98 No.7 Mk 6 bomb model 2
  • Type 1 No.7 Mk 6 bomb model 3 mod 1

Gas bombs[edit]

  • No. 6 Mk 1
  • Type 1 No.6 Mk.1
  • Type 4 No.6 Mk 1

Cluster type bombs[edit]

  • Type 2 No.6 Mk 21 bomb model 1
  • Type 2 No.6 Mk 21 bomb model 2
  • 1 kg hollow-charge bomb
  • 1 kg anti-personnel bomb

Practice bombs[edit]

  • 1 kg Practice bomb Mod 2
  • 1 kg Practice bomb Mod 3
  • No.3 Practice bomb Model 1
  • Type 99 No.3 Practice bomb

Flares[edit]

  • Type 96 landing flare
  • Landing flare
  • 5 kg parachute flare Model 2 mod 1
  • Type 0 parachute flare Model 1
  • Type 0 parachute flare Model 1 mod 1
  • Type 0 parachute flare Model 2
  • Type 0 parachute flare Model 3 mod 1
  • Experimental model 11 parachute flare
  • Type 94 float light
  • Experimental float light
  • Type 94 model 2 float light
  • Type 0 model 1 float light

Smoke floats and markers[edit]

  • 2 kg smoke float
  • 43 kg smoke float
  • Type 0 Model 1 sea marker
  • Type 0 Model 2 sea marker
  • Cardboard type sea marker
  • Type 3 No.6 target marker bomb
  • Type 2 2 kg target indicator

Misc[edit]

  • 2 kg Window (Chaff) bomb

Fuzes[edit]

Japanese Navy bomb fuzes designation system was unknown to the Allies until after the end of the Second World War. As a result a designation system was created to describe the fuzes as follows. It consists of a capital letter, a numeral and a lower-case parenthetical letter.

The capital letter designates the fuzes type as follows:

  • A - nose impact
  • B - tail impact
  • C - long delay fuze
  • D - airburst fuze
  • E - protective fuze

The numeral approximates the order in which the fuzes were captured by the allies. Finally the lower-case letter in parentheses indicates the different but similar designs.

Where possible the original Japanese designation is given.

  • A-1(a)
  • A-1(b)
  • A-1(c)
  • A-3(a) Type 97 Mk 2 nose fuze
  • A-3(b) Type 1 nose fuze model 2
  • A-3(c) Type 2 nose indicator
  • A-3(d) Type 97 Mk 2 nose fuze Model 1
  • A-3(e) Type 3 nose indicator
  • A-3(f) Type 2 No.50 Ordinary bomb fuze model 1
  • A-3(g)
  • A-5(a)
  • B-2(a) Type 99 No.25 Ordinary bomb fuze
  • B-2(b) Type 99 No.80 Mk 5 Bomb fuze
  • B-3(a) Type 15 tail fuze model 2
  • B-3(b) Type 15 tail fuze model 1
  • B-5(b)
  • B-5(c)
  • B-6(a) Type 97 rail initiator
  • B-9(a) tail fuze
  • B-10(a) tail fuze
  • C-1(a) Type 99 special bomb fuze
  • C-2(a) Type 99 special bomb nose fuze
  • D-2(a)
  • D-2(b)
  • D-2(c)
  • D-3(a)
  • D-4(a) parachute flare fuze
  • Type 3 electric firing device

See also[edit]

References[edit]

  1. ^ See List of List of Japanese World War II explosives for explanation of various explosive types
  2. ^ a b c d e f g h i j k l Japanese Bombs, "Intelligence Targets Japan" (DNI) of September 1945. U.S. Naval technical mission to Japan. December 1945. 
  3. ^ a b c "THE JAPANESE STORY OF THE BATTLE OF MIDWAY". ONI (Office of Naval Intelligence). 1947. Retrieved 2007-05-08. 
  4. ^ TM 9-1985-4 notes this as probably
  5. ^ Excluding weight of tail
  6. ^ TM 9-1985-4, Japanese Explosive Ordnance