List of Japanese World War II navy bombs

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

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

Bomb type/ mark	Marking scheme				Alternate marking scheme				Purpose
Bomb type/ mark	Nose color / band color	Body color	Tail color	Body band color	Nose color / band color	Body color	Tail color	Body band color	Purpose
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

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

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

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

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

Cluster type bombs

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

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

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

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

2 kg Window (Chaff) bomb

Fuzes

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

References

↑ See List of List of Japanese World War II explosives for explanation of various explosive types
1 2 3 4 5 6 7 8 9 10 11 12 Japanese Bombs, "Intelligence Targets Japan" (DNI) of September 1945. U.S. Naval technical mission to Japan. December 1945.
1 2 3 "THE JAPANESE STORY OF THE BATTLE OF MIDWAY". ONI (Office of Naval Intelligence). 1947. Retrieved 2007-05-08.
↑ TM 9-1985-4 notes this as probably
↑ Excluding weight of tail
↑ TM 9-1985-4, Japanese Explosive Ordnance

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