In this section we will talk about specific kind of civilians masks. They were used in Air Defense. Then, I will show you all the info I have about them and I'll post pics about them:

Recently, with a good friend, we discovered the correct name for this kind of mask. It is ''Kou''.

-Fabric Kou Mask: The earliest of this serie was made of a thick canvas type material as opposed to rubber which was used for later versions. The mask had a head harness made of wide fabric straps which were adjustable around the chin area on each side. It featured a single plastic eye shield and a small fixed filter cartridge on the front of the face piece. This configuration was used on at least two other Japanese civilian gas masks during the war. Thousands of these masks were issued to civilians in case of chemical attack or for firefighting.

Mine is marked Showa 17(1942). And It is a size 2 (Medium). Here's some photos of it:

-Fabric Kou Mask with Exhale Valve: This one is same kind of mask as the previous model, but it has an exhale valve on the left side. This can be a kind of experimental mask or a mask with a very limited production. It is marked Showa 17(1942). It is a size 3 (Big). Notice the filter is bigger than on the other models.
Here's a pic of mine::

-Kou Green Rubber Gas Mask: This mask is the rubberized evolution of the fabric one. It has same harness distribution and same kind of plastic eye. The harness has been rubberized also. It's the most common model. Mine is marked Showa 18(1943) and It's a size 2. The size is written inside in the right part, on the left is the manufacturer's symbol.

Koy Green rubber with exhale valve: it is a ¿size 2 (Medium)? and marked in showa 18 (1943)

-Kou Black Rubber Mask. This one is same model than the 2 previous but in black rubber. The production is more belated. For example, mine is marked Showa 19 (1944). It has same harness and filter design and the plastic lense has same form and size than previous models. This one, I guess it's a size 1(Small). 

-Kou Black Rubber Mask with Exhale Valve: This one, as the fabric mask with exhale valve, may be an experimental mask, prototype or had a very limited production. It is the same as the black rubber model but with an exhale valve on left side. It has same design than all previous masks. It is marked Showa 19(1944) and I think it is a size 3(Big). Notice that the filters are bigger on gas masks with exhale valve. 

I have been thinking that civilian masks with a size 3 (big) can have this kind of exhale valve, but it's just my own theory.

Unkown Civilian Mask:
This mask was made by Trade Mark. Seems to be an upgrade of the civilian type 16. This one is still keeping the original box and carrying bag. Inside the filter is still blocked by a corc. Not much info is in the box or markings, Just instructions how to use it. It has got a three point harness.

It has got an exhale valve at the back left and the corc is still blocking the inside valve.


Prototype Gas Mask

Here we have what I think it is a kind of prototype/experimental/reduce production/ high voltage piece gas mask.

We dont have information about any model like this one. I have the theory that it is a japanese gas mask. Let's present the mask:

It actually looks like the british civilian model from WW2, but the big differents are:
-The filter is shaped as a japanese filter.
-It has two exhale valves in each side of the mask.
-And the rubber is quite more strong as the british mask.

Now we will check the filter:
As I said before, it really remember us the shape of japanese filters from WW2. The ''32'' is one of the very little marks it has.
The inside of this mask is quite interesting. It has a kind of diffuser of the entrance of air attached by snaps buttons.

And here we have a close shot of those snaps buttons, any information about them will be quite appreciated:

If we remove this kind of diffuser, we can see the filter, that really remember us the inside of the type 17 civilian gas mask:

I would consider this mask as a late war prototype of the civilian gas masks.