Hello everyone! Today I’ll be putting forward to you what I hope will be the most comprehensive and up to date study and examination of the weapon I intend to suggest for Japan, the Hinō-Komuro M1904 Pistol & Some potential Hinō-Komuro M1904 variants!
This will be just as much of a suggestion as it will be an in-depth report of the history, development and variants based upon prior and new found information.
Due to the expansive coverage that will take place herein and the extensive length of this report, some notably large portions of text shall be condensed and categorised for ease of reading access and selection of information for the reader.
For the reader who simply wishes to know what variants, what calibres, magazine capacity and new potential function I suggest proceeding to Section (𝒅.) & Section (𝒆.)
And a special thank you to the assistance in locating specific documentation, advice and translation assistance from @_DELAVR
(𝒂.) General Design & Specifications
1. Original Design Overview
- Original Design Overview
Earliest Production Complete (7.65mm) Hinō-Komuro Pistol currently known, all original/1st Variation components
The first ever documented recording of the initial design pertaining to the Hinō-Komuro Pistol dates back to 1897, where it’s Inventor Kumazo Hinō of whom would become an Imperial Army Lieutenant by the time of 1903 December 7th, the same time at which the initial application for a Japanese Patent covering a 7.65mm (.32 ACP/7.65mm Browning) blow forward pistol design was submitted by both Hinō Kumazo and civilian Tomojiro Komuro.
Where it would be later accepted in 1904 March 5th, formally under Patent No. 7165; within the U.S and England it was additionally granted a patent in 1907, a subsequent renewal and final issuing was made in 1908.
(See section 𝒃.1&2 for a deeper comprehensive patent history)
The operation and manipulation of the firearm was novel and unique in a number of ways that made is distinct from many firearms even to today, though not every design decision could be called practical.
The action of the Hinō-Komuro M1904 requires the user to grip a serrated face either side of the barrel itself, pulling forward until the barrel latches forward, additionally you’ll notice the breech is clear of the barrel via the top ejection port.
Another way in which the user could cock the pistol in an urgent situation or due to the barrel heating from extended fire, is by depressing the trigger thereby releasing the main spring tension upon the barrel (whilst taking care to not depress the grip safety), the user can then snap their wrist downwards and the inertia alone will be enough to cock the barrel forward, readying the pistol to fire once again. Additionally the barrel extends forward 38mm when readied to fire.
After the pistol has been loaded and cocked, the user can then depress the grip safety and pull the trigger to fire a shot. The barrel once cocked additionally activates a feeder that strips a cartridge from the magazine, at the moment the barrel comes rearward the cartridge is picked up and struck against a fixed firing pin at the back of the breech.
To reload a Hinō-Komuro pistol one would simply depress the lower lever located below that of the grip safety releasing the magazine from the magazine well, insert a fresh magazine and ready yourself to fire following the cocking procedure once more if performing a full reload from empty.
Additionally as noted in later sections 𝒄.1&2 and explained in greater detail within section 𝒆., if one depresses the trigger only partially instead of the entire length of the trigger pull, it is possible to prevent the firing and retaining detent from full engaging with the firing shoulders, thereby causing the Hinō-Komuro M1904 pistol to fire within bursts or full-auto until the magazine is emptied or the trigger is released or pulled fully rearward.
(See section 𝒆. for the full breakdown concerning full-auto/burst-fire “capability”)
2. Focus Upon The 8mm (8x22mm Nambu) Version
- Focus Upon The 8mm (8x22mm Nambu) Version
Why suggest the 8mm over the 7.65mm?
To give a brief explanation for the latter part of this report and the primary body of the suggestion, I’ll be predominantly suggesting the Hinō-Komuro M1904 chambered within 8mm (8x22mm Nambu) despite the fact that most surviving examples up to the current day have been chambered in 7.65mm (.32 ACP/ 7.65mm Browning).
The two main reasons are directly because of the intended and desired performance in game, as most of the 8mm Hinō-Komuro pistols exhibit the most modern features of the pistol’s development, in addition to the 8x22mm Nambu being a more potent cartridge than that of the 7.65mm Browning. Secondly, the magazine capacity of both calibres is exactly the same; logically it makes the most sense to primarily suggest the “best” version of the Hinō-Komuro M1904 to be put in game, first and foremost.
Nevertheless I will still put forward the information for other possible calibre variants that come with their own distinct differences.
(See section 𝒅.2&3 to view all information concerning calibre variants and magazine capacity.)
3. Changes to the Design & Component Variation
- Changes to the Design & Component Variation
In this section I will put forward the design and component variations known thanks to surviving examples, the US and Original Japanese Patent drawing in a side by side, in addition to a table extrapolated directly from P.35, Japanese Military Cartridge Handguns 1893-1945
A Revised and Expanded Edition of “Hand Cannons of Imperial Japan”
To give a quick summary these modifications and variations primary consist of the following changes in the areas of:
- Barrel length.
- Firing pin and breechblock scheme.
- Sight design.
- Receiver contour.
- Grip frame and safety shape.
- Grip panel checkering pattern.
- Grip panel retainer arrangement.
- Magazine body design.
- Magazine latch design.
- Magazine base configuration.
Design Evolution of the Hinō-Komuro
| Components and Features | Japanese Patent | United States Patent | Serial No. 31 | Serial No. 56 | Serial No. 69 | Serial No. 372 |
|---|---|---|---|---|---|---|
| Barrel Length | 203 mm | 203 mm | 203 mm | 194 mm | 194 mm | 194 mm |
| Firing Pin and Breech Block | Original | 1st Variation | 1st Variation | 1st Variation | 1st Variation | 1st Variation |
| Sights: • Front • Rear |
Original Original |
1st Variation Original |
1st Variation Original |
1st Variation 1st Variation |
1st Variation 1st Variation |
1st Variation 1st Variation |
| Receiver Contour | Original | 1st Variation | 1st Variation | 2nd Variation | 2nd Variation | 2nd Variation |
| Grip Frame and Safety | Original | 1st Variation | 1st Variation | 2nd Variation | 2nd Variation | 2nd Variation |
| Grip Panels: • Checkering • Retainer |
Unknown Original |
Unknown Original |
1st Pattern Original |
2nd Pattern 1st Variation |
3rd Pattern 2nd Variation |
4th Pattern 2nd Variation |
| Magazine: • Body • Latch • Base |
Original Original Original |
Original 1st Variation Original |
Original 1st Variation Original |
1st Variation 2nd Variation 1st Variation |
1st Variation 2nd Variation Non-original |
1st Variation 2nd Variation 2nd Variation |
A Revised and Expanded Edition of “Hand Cannons of Imperial Japan”
Harry L. Derby III & James D. Brown
For further clarity in identifying the differences refer to the aforementioned Serial Numbers and their accompanying pistols below. Additionally at bottom will be a 8x22mm Hinō-Komuro M1904, Serial No. 126 and list the component variations of said pistol.
| Components and Features |
Serial No. 126 |
|---|---|
| Barrel Length | 194 mm |
| Firing Pin and Breech Block |
1st Variation |
| Sights: • Front • Rear |
1st Variation 1st Variation |
| Receiver Contour | 2nd Variation |
| Grip Frame and Safety |
2nd Variation |
| Grip Panels: • Checkering • Retainer |
3rd Pattern 2nd Variation |
| Magazine: • Body • Latch • Base |
1st Variation 2nd Variation 2nd Variation |
(𝒃.) Original Patent Drawing & US Patent
1. Original Patent Drawing
- Original Patent Drawing
In this section I’ll present to you the original design drawing of the Hinō-Komuro M1904 pistol and how it’s been applied in a literal sense upon the pistols themselves outside of their mechanical function.
As mentioned in the previous section (𝒂.) General Design & Specifications, paragraph 1. The original concept for the Hinō-Komuro Pistol (at times simply referred to as the Kumazo Hinō blow forward mechanism) was first recorded in 1897, the first finalised design was finished in December 1903 and was then put forth for the initial Japanese patent on the 7th of the same month. “特許 (Tokkyo) Patent Number 7165.” To which it was later obtained on March 5th, 1904.
In my research I came across a digital diary of sorts that speaks of an aviation museum located in Kumamoto Prefecture, Hitoyoshi City, Hokozo, that held an exhibit on Kumazo Hinō and his flying machines, in addition to the original patent drawing.
Source: Photograph of Captain Kumazo Hinō’s documents at Hokozo in Hitoyoshi City 2004/09/03 Masa
2. Subsequent Patent History & Full US Patent
- Subsequent Patent History & Full US Patent
An interesting point to note in the history of the patent and production of the pistols, is that on the 8mm Hinō-Komuro M1904 pistols, on the rear section upper section of the grip there’s a stamp displaying “特許” (Tokyyo) with patent number 7165 directly below it. This was believed to be further protection of the design as the 8mm variant of the Hinō-Komuro pistol was not covered in the initial patent filings.
In the United States the patent filings for the Hinō-Komuro pistol were first submitted on September 23rd, 1904, under U.S. patent-no. 886211, the application was then renewed later on February 7th, 1908, and was then finally issued on April 28th, 1908.
I will now present to you the pages of the U.S. Patent-no. 886211 for any reader who wishes to understand the patent in full details.
UNITED STATES PATENT OFFICE.
KUMAZO HINO AND TOMIJIRO KOMURO, OF USHIGOME, TOKYO, JAPAN.
PISTOL.
No. 886,211. Specification of Letters Patent. Patented April 28, 1908.
Application filed September 23, 1904. Serial No. 225,681. Renewed February 7, 1908. Serial No. 414,780.
SECTION MOVED TO COMMENTS, EXCEEDED CHARACTER LIMIT
(𝒄.) Translation of a Factory Pamphlet in 1979 & New found Factory Pamphlet in 2026
(𝒅.) Known and Possible Variants
1. Surviving Variants
Currently today the Hinō-Komuro M1904 doesn’t have many known surviving examples, whether in 7.65mm Browning and especially in concern to the 8x22mm Nambu models. It’s suspected the serial range is from 1-500 but only up to Serial No. 445 can be confirmed at the time of writing.
I’ve spoken in depth about the 7.65mm & 8mm models, so I won’t go too in depth as the reader can find out more concerning the specifications in section (𝒂.) General Design & Specifications, 1&2.
Here I will speak of one other currently known surviving example that is perplexing in every regard. The Hinō-Komuro 7.65mm “Rework” Serial No. 32. At the time of writing there’s still no surging documentation describing, when, where and for what reason this Hinō-Komuro M1904 was so extensively modified. What we do have is a list pertaining to these modifications as follows:
2. Offered Calibre Variants by Factory
Until 1976 it was generally assumed that all Hinō-Komuro pistols were chambered in 7.65mm (7.65mm Browning), Serial No. 184 was discovered and was the first known 8mm (8x22mm Nambu) Hinō-Komuro M1904 pistol. (as mentioned earlier in section " (𝒄.) Translation of a Factory Pamphlet in 1979 & New found Factory Pamphlet in 2026")
later in 1979 thanks to the efforts of historian Atsushi Shibuya, author of The Life of Kumazo Hinō in preparation of the first edition volume he had made a request concerning the personal history of Tomojiro Komuro, the very one who assisted Kumazo Hinō in funding the development and production of the later known Hinō-Komuro pistol.
He was contacted about a home formerly owned by Komuro in the Saitama Prefecture. Within the basement of this old dwelling the historian uncovered early photographs of Tomojiro Komuro and an original factory catalogue. This catalogue offered great insight about the pistol and is how we know the factory initially offered and potentially produced the Hinō-Komuro pistol in calibres besides that of 8x22mm Nambu and 7.65mm Browning.
From the two factory pamphlets we can directly reference the calibre range from 5-8mm cartridges being an option, but what were they specifically? We can answer this by reviewing popular cartridges that were available for domestic purchase within Japan at the time, then with the knowledge of what cartridge we can assume the magazine capacity accordingly from the listed range of 8-15 rounds.
- 5mm Clement, Hinō-Komuro M1904, 15rd
| Ballistic performance | ||
|---|---|---|
| Bullet mass/type | Velocity | Energy |
| 28 gr (2 g) FMJ | 1,030 ft/s (310 m/s) | 65 ft·lbf (88 J) |
The only reasonable choice of pistol cartridge concerning the 5mm would be the 5mm Clement, it was manufactured as an early pistol cartridge for pocket pistols such as the 1903 Belgian Clement pistol and some other Spanish pistols.
Domestically such pistols were only likely purchased in very small amounts and even smaller amounts of ammo. Even so, it wouldn’t be unreasonable to imagine they were purchased by Japan with the primary purpose of distribution into Chinese markets; Spanish pistol producers were at the time unable to sell directly to China.
It’s a very small cartridge and I suspect it was 1 of the 2 cartridges offered with a 15 round magazine capacity. Though how many or whether any 5mm Hinō-Komuro pistols were made isn’t very likely, compounding this is the fact that after 1906 Clement shifted production to .32 ACP.
- 6.25mm/.25ACP, Hinō-Komuro M1904, 15rd
| Ballistic performance | ||
|---|---|---|
| Bullet mass/type | Velocity | Energy |
| 50 gr (3 g) FMJ | 760 ft/s (230 m/s) | 65 ft·lbf (88 J) |
A comparatively much more common calibre to see for pocket carry pistols in Japan is the .25ACP, used in handguns such as the Model 1910 Mauser pistol.
This cartridge is very comparable in visual size to that of the 5mm Clement, and is even shorter due to the Clement cartridge having such a long bullet. I suspect this would also be one of the calibres intended to have 15 rounds in the magazine.
If any other calibre variations asides from the 7.65mm Browning/.32ACP or 8x22mm Nambu should exist, the 6.25mm/.25ACP variant is a likely candidate.
- 7.65×21mm Parabellum/.30 Luger, Hinō-Komuro M1904
| Ballistic performance | ||
|---|---|---|
| Bullet mass/type | Velocity | Energy |
| 6.03 g (93 gr) FMJ | 370 m/s (1,200 ft/s) | 412 J (304 ft·lbf) |
Another suspected calibre offered for the Hinō-Komuro M1904 is the .30 luger, but this wasn’t a terribly common round to see in Japan except for some higher end luxury purchases of luger pistols in Japan.
This dimensionally is extremely similar to the 8x22mm Nambu cartridge, though it operates at a reasonably higher pressure than the 8mm Nambu. One point for consideration is the rim of the cartridge isn’t quite the same, accordingly it’s believed extraction might’ve been a problem without slight modification.
3. Possible “Carbine” Variant
If we refer back to the 2026 factory pamphlet that was discovered concerning the Hinō-Komuro M1904 under section, (𝒄.) Translation of a Factory Pamphlet in 1979 & New found Factory Pamphlet in 2026, 2. New 2026 Factory Pamphlet Deep Dive, Reconstructed 2026 Pamphlet & Translation, “writing inside red outlined box” we can take the pamphlet in a literal sense concerning the intended purpose and function of performing like a “Carbine”. To partially quote directly from it it says as follows:
So if we follow the advertised purpose of this configuration under that of a pseudo-carbine, we could catagorise this variant under the tentative name “Hinō-Komuro M1904 Carbine” thereby giving Japan another “pistol calibre carbine” under a technicality.
Additionally it should be noted the mention of a purpose built shoulder-stock is mentioned, this is likely an attachment that could’ve been purchased when ordering a Hinō-Komuro M1904.
(𝒆.) New Found Potential Burst Fire & Full Auto Capability
Now for one of the most interesting and peculiar quirks of the Hinō-Komuro M1904, something that wasn’t corrected through any iteration or patent application filings, and something that was noted in the 1979 Factory Catalogue & the 2026 Factory Pamphlet is a peculiar note about the pistol requiring a full firm trigger pull.
The reason for this being as both Komuro Gun Factory pamphlets state ‘- otherwise the pistol can fire two shots or more…’ additionally an attentive eye will notice that in neither pamphlet this is labled under the “Warning” sections. I’ll now provide the direct quotes from both pamphlets.
It’s incredibly peculiar that something such as the ability to fire a burst or in full-auto via a light trigger pull/half pull wasn’t corrected in any iteration. It would be a relatively simple revision of the retaining catch and or firing shoulders.
If we take this in a literal sense whilst certainly somewhat cautionary, it seems this may have been something that was once unintended and instead became a feature of the weapon. This may very well be one of the first examples of a sort of dual-stage trigger system.
Whilst it wouldn’t be very practical in real life, this could make for an interesting additional firing mode in Enlisted thereby allowing you to shoot in a burst of 2/3 shots or to shoot in full auto, all it would take is an adjustment in pressure applied to the trigger.
Availability
Based upon the extensive documentation and study of this particular pistol, I believe the Hinō-Komuro M1904 should have at least two versions in game. An 8mm Hinō-Komuro M1904 Pistol slot option, and a Stocked “Carbine” variant chambered in 6.25mm/.25ACP with a 15 round magazine. Named tentatively the “Hinō-Komuro Carbine”.
I think the pistol slot option would be great for an event item, whilst the “carbine” variant would be a unique battlepass item.
Gameplay
The gameplay of the Hinō-Komuro Pistol will provide Japan with an extremely unique domestic design, additionally if we allowed the pistol to have a select fire option of a 2 round burst or full-auto it’ll function as a domestic machine pistol.
BR
I think BR 1 is appropriate for the Hinō-Komuro Pistol & the Hinō-Komuro Carbine, even if the carbine has a burst fire or full-auto option the small magazine size plus the small calibre, I believe these are strong enough balancing levers to keep it at a low BR.
Purpose
The Hinō-Komuro Pistol shall serve as a pistol slot option, whilst the Hinō-Komuro Carbine can be considered a Pistol Calibre Carbine
Sources
https://bid.donleyauctions.com/auction/263-the-john-bannister/lot-1165-japanese-pistol/
https://www.forgottenweapons.com/wp-content/uploads/HinoKomuro/US%20Patent%20886211.pdf
- Yes, both the Pistol and Carbine
- Yes, Just the Pistol
- Yes, Just the Carbine
- No (if no explain why)
- Yes, both burst fire and full-auto
- Yes, only burst fire
- Yes, only full auto
- No, only default semi-auto
Remember your vote counts!
