Here, we continue the story of the Type 90 helmet, how they dealt with expansion of production.
First, some loose topics left over from the development story.
Prototypes and patents
Folding Helmet
During the prototyping process, inventions required to be patented by the Army, so no private person should later demand credit and royalties. One such novel idea that applied for a patent (application no. 11453, November 1928) in the course of the development of the type 90 helmet was a folding steel helmet invented by Army Artillery Captain, Tadashi Sato, a Tokyo resident. Of course, as an Army officer, Sato had already signed his consent to hand over the rights to his design to the Army in October and as with all Army patent applications, it was handled as a secret patent that does not get posted to the public.
As can be seen from the field evaluation criteria, the Army was concerned with portability of the helmet when it was not in wear. As the official designation of Close Combat equipment suggests, the helmet was a weapon item for close combat use only and not meant for general wear as part of the uniform, the visor cap still being the official headgear. Thus a folding helmet was seen as a practical solution to facilitate portability.
An example of this prototype survived and exists today in a Japanese collection.
New Steel alloy patent
In April 1933, the patent office granted patent number 100433 for a new low manganese steel alloy for helmets, using chrome, molybdenum and vanadium. This patent was applied for in December 1931 as application no. 14144 and was the invention of Army Artillery Lt. Colonel, Masakuni Sugimoto of Nishinomiya City. Though this application was made only a year after the introduction of the Type 90 helmet, there is little doubt that this was what the Type 90 announcement referred to as the special steel alloy. This same officer had also been granted a patent in 1928 for a steel alloy for bullet shields and the 1933 patent appears to be a reduced manganese variant of this earlier work.
A secret order placed by Chiang Kai-shek in Nanking in the Spring of 1930 for Japanese Weapon supply included a request for 4 helmet samples of the new helmet, but the Army order releasing these samples specifically states that they were to be supplied in non-treated steel.
This patent was later declassified on March 31, 1936 by the Army, who no longer saw the need for secrecy.
Production ramp up of the Type 90 helmet by Kobe Steel and Japan Steel Works during 1931
The Osaka Arsenal contracted Kobe Steel (神戸製鋼所) to produce Type 90 helmets as well as personal body armor, but the manufacturer soon realized they needed to do their own testing on the firing range to optimize the helmet design for large scale production, and for this built their own range, but now they had to get hold of the special rifles and ammunition that the Army developed for helmet testing. First, in a letter dated August 27th, 1931 Kobe Steel requested the Army for the supply of the Army modified rifles. One, a Murata Rifle modified to 12.6mm caliber for helmet testing, and the other a Type 38 modified to 7.7mm* for the armor program. This was immediately followed the next month with a request for 100 shots of ammunition for the guns. In order to be more efficient, Kobe Steel further decided to add testing of the steel sheets before production, and thus went back to the Army with another request for 200 rounds in October.
Then at the end of November 1931, a similar request was filed this time from the Nihon Seikou (Japan Steel Works日本製鋼) of Tokyo, who at the time was in the process of pre-production prototyping.
They requested the 12.6mm Murata Rifle and specified their required 100 rounds of test ammunition spec as one with a “300 meters residual velocity as measured 5 meters away from the gun muzzle”.
*Separate from the 7.7mm, modified Type 38 rifles prepared for armor testing, a proper 7.7mm prototyping program was
underway in 1929, which was a different gun using a shorter barrel and a larger cartridge.
Helmets to the front! (1931-1932)
On September 18, 1931, just when production of the type 90 helmets had started to pick up, the Japanese Army staged a sabotage of the railway near Mukden to create an excuse to invade Manchuria.
This was the Manchurian Incident that will lead to the establishment of Manchukuo the following year and a full-scale war with China in 1937. The Kwantung Army dispatched its troops, who arrived wearing their cherry blossom helmets received in the summer of 1928, and an order was placed for 24,780 Type 90 helmets to cover the immediate needs of the action in Manchuria. However, when in close succession, the Shanghai Incident of January 1932 broke out and stoked the fire in the Continent, the Army and Navy were all mobilizing, causing a rush for helmets.
A telegram classified “secret” dispatched on December 18th, 1931 from the Chief of Staff of the Kwantung Army addressed to the Vice Minister of the Army, reminded that the new troops to be sent to the continent should already come equipped with the new steel helmet and belts for the extreme cold climate outer wear. In order to cope with such contingency needs of newly formed units to be sent to Manchuria, the Army main arsenal was ordered to supply 1,000 helmets to the Kokura Arsenal and 3,060 pieces to the Hiroshima arsenal that month. And at the end of December, a request for 2,000 helmets from the Kwantung Army for its new troops was to be supplied to the 20th Infantry Division, which was to carry them upon their departure to the continent.
While the Navy swallowed its pride to beg the Army to sell them Army weapons and 1,700 old cherry blossom helmets to supply their Landing Forces bound for the continent, in February 1932, the Army dispatched a panicked message to its divisions remaining in Japan and its schools that they should return their type 90 helmets ASAP for forwarding to Manchuria.
Helmet donations welcome (1932-)
Whoever it was that got the idea, from this time, the Army would solicit helmet donations from the public, and thousands of helmets were donated to the cause of Manchuria already in January and February of 1932. These helmets came from the Veteran’s Leagues, The Patriot Women’s Leagues, etc, who will collect donations in cash and deliver that to the Ministry of the Army, who would have the arsenal turn them into helmets. At this time, a donation of 13.5 Yen bought the Army one helmet. This practice will continue for years, and donors would get a citation of gratitude, later ones in Tojo’s name as Minister of the Amy.
Phasing out of the cherry blossom model (1932)
Finally, by summer of 1932, the supply of the new type 90 helmets for the Manchurian Incident had stabilized, and Army Manchuria Regular Ordinance 1769(陸満普第１７６９), dated July 22nd 1932 announced that all old type helmets in the Manchurian “Incident Theater of operations (Manchuria, China and Korea)” were to be exchanged with the new Type 90 helmet stocks from the Army Depot and costs charged to the Manchurian Incident budget. With this order, the old helmets ended their front-line duty in the Army, but continued to serve their new, but second hand owner, the Navy.
From a weapon to uniform (1932-33)
By Army Regular Ordinance 2748 (陸普第２７４８) of April 28th 1932, seven items formerly categorized as “weapons” were reclassified as “clothing items”. Among the human and horse gasmasks, anti-gas wear and body armor thus reclassified was the steel helmet. Some of these gear also went through a nomenclature change through this order and the steel helmet, which was hitherto called Tetsu Kabuto (Steel Head Armor 鉄兜) was officially renamed Tetsu Bo (Steel Hat鉄帽), more in keeping with its new identity as a component of the uniform. The classification change also meant that the Clothing Main Depot (被服本廠) would now take over the helmet business from the Army Technical Headquarters, and the 1933, April memo from the Vice Minister of the Army to the Clothing Main Depot allocated a production quota of 50,000 helmets to be supplied by the end of that year, still a relatively small number.
Having production of cloth items and steel helmets under the same Army office must have made it easier for the Army to deal with the complaint from soldiers that their helmets baking in the sun were giving them serious discomfort in the field, as the clothing office promptly shipped out 3100 pieces of anti-heat helmet cover prototypes for the troops in China to test and finalize. These covers are discussed in a separate section.
Army Regular Ordinance 4525 of July 26th 1932 followed through on the helmet’s change to a clothing item by instructing all that henceforth gas mask and helmet orders were to be placed with the Clothing Main Depot. This announcement also clarified the rule regarding repair of damaged helmets, which became the responsibility of the unit. Later shipping manifestos show that field units received all the necessary pieces ( liner, padding pouch for liner, rings for the straps, star insignia and paint ) to be totally self-sufficient in repairs.
Boosting production (1935-36)
During November to December of 1935, Nihon Tokushu Ko ( Japan Special Steel日本特殊鋼) of Tokyo obtained its tools of the trade, two modified 12.6mm Murata rifles and 1,000 rounds of the special helmet-testing rounds to join as a helmet manufacturer.
Another manufacturer, Daido Steel Company (大同製鋼) of Nagoya, also got tapped on the shoulder by the Osaka Arsenal around the same time and placed their request for the antique weapon the next month, in January of 1936.
In this manner, what started out as an annual production volume of 71,750 helmets in 1931 reached 430,000 units of accumulated production by 1936, and then in 1937 alone 420,000 were made, almost matching 6 years of production in a single year. Though production figures are not available from 1938 onwards, annual production is estimated to have been between 400 and 700 thousand units a year.
Type 90 Helmet Supply to the Navy (1931-37)
During 1931 and 1932, many ships operating off Chinese shores put in requisitions for steel helmets for its Landing Force troops and gun crews, but none of these requisition forms specify helmet type until a requisition form dated June 8, 1933 from the Naval Propaganda Office requested 50 pieces of “Model 2” helmets along with an armored car from the Shanghai Incident for PR. The Navy had bought 1,700 Cherry Blossom helmets from the Army in February 1932 for the Shanghai Incident, so now model names were given to tell them apart, giving rise to “Model 1”and “Model 2” designations.
The first requisition document that confirms availability of the”Model 3” or Type 90 is dated November 9, 1933 in which 280 Model 3s were supplied to the 26th Destroyer Fleet and all the requisitions from the beginning of 1934 consistently mention Model 3s by name, indicating that the type 90 helmet did not see too much circulation within the Navy until 1934. Circulation is the right word, because these were “loan” items in the Navy, and once the ship was taken off patrol duty of the Chinese coast, the helmets were returned to the depot for loan to other ships and their Landing Forces. As mentioned before, they were special weapons loaned out when close encounter with the enemy was anticipated. That changed for the Army when they shifted helmets to the clothing category, while the Navy persisted to treat them as weapons, suffering shortages when general mobilizations created a rush for the limited weapons supply.
Isoroku Yamamoto was still deskbound as the Vice Minister of the Navy when full-scale war with China (The China Incident) broke out in July 1937, causing an “all alert” situation. The following letter from him to his counterpart at the Army illustrates the Navy’s situation regarding helmets.
------------------------------------------------------------------------------------------------------------------------------------------
The advancing of steel helmet inventory August 25, 1937
Due to this incident we find ourselves in urgent need of the weapons below and would be grateful if you would arrange for us to draw from the inventory of your Ministry.
I would like to initiate discussions between those in charge at the working level on this matter. We will replace your stock by placing an order with the Army Clothing Main Depot.
Steel Helmets (Official Army Standard Model) 4,000 Pieces
Isoroku Yamamoto
Vice Minister of the Navy
Note Yamamoto’s reference to the helmets as a “weapon”. Also, the word for steel helmet he uses is the pre-1932 word Steel Head Armor.
Other users of the type 90 helmet (War correspondents and Export)
The Army design helmets were strictly military and were not available to civilians, but there were a handful of cases where Type 90s were produced without the Army star insignia in front for use outside the Japanese Army.
One of these exceptions was helmets for war correspondents requested by Asahi Newspaper and Domei News Agency issued in 1939.
A letter from Asahi to the Minister of the Army, dated June 17, 1939 explains, “In light of the fact that our correspondents, photographers and messengers, who have nobly given their lives to the current China Incident have all fallen due to being shot in the head…” and requested permission to procure 100 helmets for the use by such staff. In August, the other major media company, Domei News Agency made a similar request for its 50 front line newspapermen. The Army’s production order for these helmets specifies omission of the Star Insignia.
Also, in the early days of the Type 90 helmet, frequent requisitions for Army helmets without insignia can be found coming from an organization named “The Taihei Association (World Peace Association泰平組合)”. The irony of the name is that they were an exporter of Japanese surplus weapons.
After the Russo-Japanese War, Japan’s active weapons development rendered many weapons obsolete and the trading houses Mitsui, Okura and Takada were competing with each other in buying them up and exporting them to countries such as China, England and Russia. When Lt. General Nambu of the Type 14 pistol fame noticed the three companies bidding against each other only to benefit the foreign buyers, he suggested that they should rather team up than compete, which took the form of the Taihei Association.
They changed names in 1939 April to Showa Trading when Takada dropped out and was replaced by Mitsubishi.
They are shown to have shipped untreated steel versions of the type 90 prototype samples to Chiang Kai-shek in 1930, samples to Mexico in 1935 and 1939, to Peru in 1936 and 1,000 helmets to Mongolia in 1940. These were normally supplied with other weapons. These helmets, too, were devoid of any star insignia.
The Heavy Duty Variant (Type 98) Helmet (1932-1939)
Readers may recall that when Kobe Steel got involved in steel helmets back in 1931, it was also given the personal armor project. The Type 38 rifle, modified to 7.7mm caliber was the special test weapon for that project. One may also recall that the development objective of the Type 90 helmet was to make it as light as possible “even if the protective attributes had to be compromised within reason”.
As would be expected, the wearability of the helmet had its cost in lives during the Manchurian Incident when taking fortified enemy positions required close range fighting, typically exposing combat engineers.
With such users in mind, a “bullet proof” helmet was included in the personal armor program and studies began in May of 1932.
The trade-off between weight and wearability according to the feedback from the Infantry and Engineer Schools involved in field evaluations and also the Army Medical School was that, 1 kilogram (what the Type 90 weighed) was the maximum load one could constantly keep on the head, but if it were for only a limited time, a load of up to 3 kilograms to the head would be tolerable.
Between 1934 and 1937, Kobe Steel made 32 prototypes, including a German style design, but they finally settled to keep the Type 90 shape, and doubled the thickness of the steel to approx. 2mm from the 1mm. This meant that the weight would also almost double, now weighing 1.9 kilograms. However,
this allowed the helmet to withstand a direct hit at 500 meters from the 7.7mm round, which would have penetrated a standard type 90 from 1000 meters away. Furthermore a 2mm thick detachable armor plate weighing 0.9 kilograms could be screwed onto the front of the helmet to withstand hits at 300 meters. Other changes to the type 90 included extending the chin straps by 20 centimeters and using kapok or plant sponge from Japanese gourds for the padding to enhance shock absorption.
This model was finalized in 1938, August and approved for use.
The Army’s Scientific Research Institute requisitioned 10 type 90 helmet shells in January 1934 for “Alloy research”, but whether that resulted in any improvements is questionable.
Though some claim this helmet received the official designation of Type 98 helmet, this author has not been able to confirm this in documents from the time. Rather when the Army set up a Close Combat Advisory Commission to study techniques and weapons for assaulting fortified enemy positions, their field study report of December 1938 included comparisons between using the detachable armor plate on a normal helmet and the helmet described above, which they called the “Heavy Steel Helmet”. This terminology remained in use when the Infantry and Engineer Schools also joined these studies from late 1939 and put in their requisitions for these helmets along with the famous turtle shell armor and all forms of bullet shields, flame throwers and the like.
First, some loose topics left over from the development story.
Prototypes and patents
Folding Helmet
During the prototyping process, inventions required to be patented by the Army, so no private person should later demand credit and royalties. One such novel idea that applied for a patent (application no. 11453, November 1928) in the course of the development of the type 90 helmet was a folding steel helmet invented by Army Artillery Captain, Tadashi Sato, a Tokyo resident. Of course, as an Army officer, Sato had already signed his consent to hand over the rights to his design to the Army in October and as with all Army patent applications, it was handled as a secret patent that does not get posted to the public.
As can be seen from the field evaluation criteria, the Army was concerned with portability of the helmet when it was not in wear. As the official designation of Close Combat equipment suggests, the helmet was a weapon item for close combat use only and not meant for general wear as part of the uniform, the visor cap still being the official headgear. Thus a folding helmet was seen as a practical solution to facilitate portability.
An example of this prototype survived and exists today in a Japanese collection.
New Steel alloy patent
In April 1933, the patent office granted patent number 100433 for a new low manganese steel alloy for helmets, using chrome, molybdenum and vanadium. This patent was applied for in December 1931 as application no. 14144 and was the invention of Army Artillery Lt. Colonel, Masakuni Sugimoto of Nishinomiya City. Though this application was made only a year after the introduction of the Type 90 helmet, there is little doubt that this was what the Type 90 announcement referred to as the special steel alloy. This same officer had also been granted a patent in 1928 for a steel alloy for bullet shields and the 1933 patent appears to be a reduced manganese variant of this earlier work.
A secret order placed by Chiang Kai-shek in Nanking in the Spring of 1930 for Japanese Weapon supply included a request for 4 helmet samples of the new helmet, but the Army order releasing these samples specifically states that they were to be supplied in non-treated steel.
This patent was later declassified on March 31, 1936 by the Army, who no longer saw the need for secrecy.
Production ramp up of the Type 90 helmet by Kobe Steel and Japan Steel Works during 1931
The Osaka Arsenal contracted Kobe Steel (神戸製鋼所) to produce Type 90 helmets as well as personal body armor, but the manufacturer soon realized they needed to do their own testing on the firing range to optimize the helmet design for large scale production, and for this built their own range, but now they had to get hold of the special rifles and ammunition that the Army developed for helmet testing. First, in a letter dated August 27th, 1931 Kobe Steel requested the Army for the supply of the Army modified rifles. One, a Murata Rifle modified to 12.6mm caliber for helmet testing, and the other a Type 38 modified to 7.7mm* for the armor program. This was immediately followed the next month with a request for 100 shots of ammunition for the guns. In order to be more efficient, Kobe Steel further decided to add testing of the steel sheets before production, and thus went back to the Army with another request for 200 rounds in October.
Then at the end of November 1931, a similar request was filed this time from the Nihon Seikou (Japan Steel Works日本製鋼) of Tokyo, who at the time was in the process of pre-production prototyping.
They requested the 12.6mm Murata Rifle and specified their required 100 rounds of test ammunition spec as one with a “300 meters residual velocity as measured 5 meters away from the gun muzzle”.
*Separate from the 7.7mm, modified Type 38 rifles prepared for armor testing, a proper 7.7mm prototyping program was
underway in 1929, which was a different gun using a shorter barrel and a larger cartridge.
Helmets to the front! (1931-1932)
On September 18, 1931, just when production of the type 90 helmets had started to pick up, the Japanese Army staged a sabotage of the railway near Mukden to create an excuse to invade Manchuria.
This was the Manchurian Incident that will lead to the establishment of Manchukuo the following year and a full-scale war with China in 1937. The Kwantung Army dispatched its troops, who arrived wearing their cherry blossom helmets received in the summer of 1928, and an order was placed for 24,780 Type 90 helmets to cover the immediate needs of the action in Manchuria. However, when in close succession, the Shanghai Incident of January 1932 broke out and stoked the fire in the Continent, the Army and Navy were all mobilizing, causing a rush for helmets.
A telegram classified “secret” dispatched on December 18th, 1931 from the Chief of Staff of the Kwantung Army addressed to the Vice Minister of the Army, reminded that the new troops to be sent to the continent should already come equipped with the new steel helmet and belts for the extreme cold climate outer wear. In order to cope with such contingency needs of newly formed units to be sent to Manchuria, the Army main arsenal was ordered to supply 1,000 helmets to the Kokura Arsenal and 3,060 pieces to the Hiroshima arsenal that month. And at the end of December, a request for 2,000 helmets from the Kwantung Army for its new troops was to be supplied to the 20th Infantry Division, which was to carry them upon their departure to the continent.
While the Navy swallowed its pride to beg the Army to sell them Army weapons and 1,700 old cherry blossom helmets to supply their Landing Forces bound for the continent, in February 1932, the Army dispatched a panicked message to its divisions remaining in Japan and its schools that they should return their type 90 helmets ASAP for forwarding to Manchuria.
Helmet donations welcome (1932-)
Whoever it was that got the idea, from this time, the Army would solicit helmet donations from the public, and thousands of helmets were donated to the cause of Manchuria already in January and February of 1932. These helmets came from the Veteran’s Leagues, The Patriot Women’s Leagues, etc, who will collect donations in cash and deliver that to the Ministry of the Army, who would have the arsenal turn them into helmets. At this time, a donation of 13.5 Yen bought the Army one helmet. This practice will continue for years, and donors would get a citation of gratitude, later ones in Tojo’s name as Minister of the Amy.
Phasing out of the cherry blossom model (1932)
Finally, by summer of 1932, the supply of the new type 90 helmets for the Manchurian Incident had stabilized, and Army Manchuria Regular Ordinance 1769(陸満普第１７６９), dated July 22nd 1932 announced that all old type helmets in the Manchurian “Incident Theater of operations (Manchuria, China and Korea)” were to be exchanged with the new Type 90 helmet stocks from the Army Depot and costs charged to the Manchurian Incident budget. With this order, the old helmets ended their front-line duty in the Army, but continued to serve their new, but second hand owner, the Navy.
From a weapon to uniform (1932-33)
By Army Regular Ordinance 2748 (陸普第２７４８) of April 28th 1932, seven items formerly categorized as “weapons” were reclassified as “clothing items”. Among the human and horse gasmasks, anti-gas wear and body armor thus reclassified was the steel helmet. Some of these gear also went through a nomenclature change through this order and the steel helmet, which was hitherto called Tetsu Kabuto (Steel Head Armor 鉄兜) was officially renamed Tetsu Bo (Steel Hat鉄帽), more in keeping with its new identity as a component of the uniform. The classification change also meant that the Clothing Main Depot (被服本廠) would now take over the helmet business from the Army Technical Headquarters, and the 1933, April memo from the Vice Minister of the Army to the Clothing Main Depot allocated a production quota of 50,000 helmets to be supplied by the end of that year, still a relatively small number.
Having production of cloth items and steel helmets under the same Army office must have made it easier for the Army to deal with the complaint from soldiers that their helmets baking in the sun were giving them serious discomfort in the field, as the clothing office promptly shipped out 3100 pieces of anti-heat helmet cover prototypes for the troops in China to test and finalize. These covers are discussed in a separate section.
Army Regular Ordinance 4525 of July 26th 1932 followed through on the helmet’s change to a clothing item by instructing all that henceforth gas mask and helmet orders were to be placed with the Clothing Main Depot. This announcement also clarified the rule regarding repair of damaged helmets, which became the responsibility of the unit. Later shipping manifestos show that field units received all the necessary pieces ( liner, padding pouch for liner, rings for the straps, star insignia and paint ) to be totally self-sufficient in repairs.
Boosting production (1935-36)
During November to December of 1935, Nihon Tokushu Ko ( Japan Special Steel日本特殊鋼) of Tokyo obtained its tools of the trade, two modified 12.6mm Murata rifles and 1,000 rounds of the special helmet-testing rounds to join as a helmet manufacturer.
Another manufacturer, Daido Steel Company (大同製鋼) of Nagoya, also got tapped on the shoulder by the Osaka Arsenal around the same time and placed their request for the antique weapon the next month, in January of 1936.
In this manner, what started out as an annual production volume of 71,750 helmets in 1931 reached 430,000 units of accumulated production by 1936, and then in 1937 alone 420,000 were made, almost matching 6 years of production in a single year. Though production figures are not available from 1938 onwards, annual production is estimated to have been between 400 and 700 thousand units a year.
Type 90 Helmet Supply to the Navy (1931-37)
During 1931 and 1932, many ships operating off Chinese shores put in requisitions for steel helmets for its Landing Force troops and gun crews, but none of these requisition forms specify helmet type until a requisition form dated June 8, 1933 from the Naval Propaganda Office requested 50 pieces of “Model 2” helmets along with an armored car from the Shanghai Incident for PR. The Navy had bought 1,700 Cherry Blossom helmets from the Army in February 1932 for the Shanghai Incident, so now model names were given to tell them apart, giving rise to “Model 1”and “Model 2” designations.
The first requisition document that confirms availability of the”Model 3” or Type 90 is dated November 9, 1933 in which 280 Model 3s were supplied to the 26th Destroyer Fleet and all the requisitions from the beginning of 1934 consistently mention Model 3s by name, indicating that the type 90 helmet did not see too much circulation within the Navy until 1934. Circulation is the right word, because these were “loan” items in the Navy, and once the ship was taken off patrol duty of the Chinese coast, the helmets were returned to the depot for loan to other ships and their Landing Forces. As mentioned before, they were special weapons loaned out when close encounter with the enemy was anticipated. That changed for the Army when they shifted helmets to the clothing category, while the Navy persisted to treat them as weapons, suffering shortages when general mobilizations created a rush for the limited weapons supply.
Isoroku Yamamoto was still deskbound as the Vice Minister of the Navy when full-scale war with China (The China Incident) broke out in July 1937, causing an “all alert” situation. The following letter from him to his counterpart at the Army illustrates the Navy’s situation regarding helmets.
------------------------------------------------------------------------------------------------------------------------------------------
The advancing of steel helmet inventory August 25, 1937
Due to this incident we find ourselves in urgent need of the weapons below and would be grateful if you would arrange for us to draw from the inventory of your Ministry.
I would like to initiate discussions between those in charge at the working level on this matter. We will replace your stock by placing an order with the Army Clothing Main Depot.
Steel Helmets (Official Army Standard Model) 4,000 Pieces
Isoroku Yamamoto
Vice Minister of the Navy
Note Yamamoto’s reference to the helmets as a “weapon”. Also, the word for steel helmet he uses is the pre-1932 word Steel Head Armor.
Other users of the type 90 helmet (War correspondents and Export)
The Army design helmets were strictly military and were not available to civilians, but there were a handful of cases where Type 90s were produced without the Army star insignia in front for use outside the Japanese Army.
One of these exceptions was helmets for war correspondents requested by Asahi Newspaper and Domei News Agency issued in 1939.
A letter from Asahi to the Minister of the Army, dated June 17, 1939 explains, “In light of the fact that our correspondents, photographers and messengers, who have nobly given their lives to the current China Incident have all fallen due to being shot in the head…” and requested permission to procure 100 helmets for the use by such staff. In August, the other major media company, Domei News Agency made a similar request for its 50 front line newspapermen. The Army’s production order for these helmets specifies omission of the Star Insignia.
Also, in the early days of the Type 90 helmet, frequent requisitions for Army helmets without insignia can be found coming from an organization named “The Taihei Association (World Peace Association泰平組合)”. The irony of the name is that they were an exporter of Japanese surplus weapons.
After the Russo-Japanese War, Japan’s active weapons development rendered many weapons obsolete and the trading houses Mitsui, Okura and Takada were competing with each other in buying them up and exporting them to countries such as China, England and Russia. When Lt. General Nambu of the Type 14 pistol fame noticed the three companies bidding against each other only to benefit the foreign buyers, he suggested that they should rather team up than compete, which took the form of the Taihei Association.
They changed names in 1939 April to Showa Trading when Takada dropped out and was replaced by Mitsubishi.
They are shown to have shipped untreated steel versions of the type 90 prototype samples to Chiang Kai-shek in 1930, samples to Mexico in 1935 and 1939, to Peru in 1936 and 1,000 helmets to Mongolia in 1940. These were normally supplied with other weapons. These helmets, too, were devoid of any star insignia.
The Heavy Duty Variant (Type 98) Helmet (1932-1939)
Readers may recall that when Kobe Steel got involved in steel helmets back in 1931, it was also given the personal armor project. The Type 38 rifle, modified to 7.7mm caliber was the special test weapon for that project. One may also recall that the development objective of the Type 90 helmet was to make it as light as possible “even if the protective attributes had to be compromised within reason”.
As would be expected, the wearability of the helmet had its cost in lives during the Manchurian Incident when taking fortified enemy positions required close range fighting, typically exposing combat engineers.
With such users in mind, a “bullet proof” helmet was included in the personal armor program and studies began in May of 1932.
The trade-off between weight and wearability according to the feedback from the Infantry and Engineer Schools involved in field evaluations and also the Army Medical School was that, 1 kilogram (what the Type 90 weighed) was the maximum load one could constantly keep on the head, but if it were for only a limited time, a load of up to 3 kilograms to the head would be tolerable.
Between 1934 and 1937, Kobe Steel made 32 prototypes, including a German style design, but they finally settled to keep the Type 90 shape, and doubled the thickness of the steel to approx. 2mm from the 1mm. This meant that the weight would also almost double, now weighing 1.9 kilograms. However,
this allowed the helmet to withstand a direct hit at 500 meters from the 7.7mm round, which would have penetrated a standard type 90 from 1000 meters away. Furthermore a 2mm thick detachable armor plate weighing 0.9 kilograms could be screwed onto the front of the helmet to withstand hits at 300 meters. Other changes to the type 90 included extending the chin straps by 20 centimeters and using kapok or plant sponge from Japanese gourds for the padding to enhance shock absorption.
This model was finalized in 1938, August and approved for use.
The Army’s Scientific Research Institute requisitioned 10 type 90 helmet shells in January 1934 for “Alloy research”, but whether that resulted in any improvements is questionable.
Though some claim this helmet received the official designation of Type 98 helmet, this author has not been able to confirm this in documents from the time. Rather when the Army set up a Close Combat Advisory Commission to study techniques and weapons for assaulting fortified enemy positions, their field study report of December 1938 included comparisons between using the detachable armor plate on a normal helmet and the helmet described above, which they called the “Heavy Steel Helmet”. This terminology remained in use when the Infantry and Engineer Schools also joined these studies from late 1939 and put in their requisitions for these helmets along with the famous turtle shell armor and all forms of bullet shields, flame throwers and the like.
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