Many of us know how
good eBay is for finding rare items. Over the years, I was amazed by the
large number of auctions for interesting Japanese military optical items
from companies like Nippon Kogaku (Nikon) and Tokyo Kogaku (Topcon). Those
items were often brought back to the USA as a war souvenir. This means that
if AOCo really made military items during WWII, then eBay was definitely the
place to find them. But no matter how hard I looked, none of the Japanese
military items I found appear to have been made by Asahi Optical Co. So
either AOCo never made military products, or they only made very specialized
items in limited numbers.
Just a few weeks ago,
I was lucky enough to track down a genuine WWII item from AOCo (thanks to an
Olympus collector from The Netherlands, who found it in a large lot of
microscope items he bought). And the item proved to be very interesting and
unique!
The label
The item came in a
olive-green case and that in itself is an indication of its military
purpose. On the lid, there’s a metal label with a lot of Japanese
characters and a serial number with Arabic numerals. Unfortunately, I am not
able to translate Japanese kanji symbols. Thanks to the translation made by
a Japanese woman (see acknowledgements section), I was able to make sense of
it.
First, we need to
realize that Japanese symbols should be read from right to left. The upper
row is, at places, hard to understand because some archaic and unknown
ideograms were used. However, it more or less translates in "Type 93 50
[unit of measure] observation item using mirrors".
The second row
contains the serial number 8411 and an unknown ideogram that probably could
be the name of the manufacturing plant.
The third row contains
the manufacturing date. The item was manufactured in the 19th year of the
Showa Era (the reign of emperor Hirohito), which means that the item was
made in 1944. There is also a number 2, which could be February, even though
the unreadable ideogram on its left does not look like being the word
"month".
The fourth row finally
proves that it was made by Asahi Optical Co., as it contains the full
official Japanese name of the company: "Asahi Kogaku Kogyo Goshi
Kaisha".
The case
When opened, the case
exposes a nice custom made wooden interior that is entirely hand finished.
The lid is leather padded to ensure that the contents of the case are firmly
seated. The contents of the case are rather strange and consists of two
separate items. First something that looks like a black painted pipe with a
triangular shaped item on one end, and a female screw thread on the other.
And just above the female screw thread there is what appears to be a
binocular eyepiece. The other item is a wooden stick that looks as if it
might have come from a black lacquered wooden stool or another piece of
furniture. The stick ends in a male screw thread and it screws into the
pipe. The resulting item looks rather odd, but with the information provided
by the seller and the information on the label it made perfectly sense,
because this item is what is essentially called a "Trench
Periscope".
Trench periscope
A periscope is an
optical device for conducting observations from a concealed or protected
position. In its simplest form, a trench periscope consists of reflecting
mirrors and/or prisms at opposite ends of a tube container. The reflecting
surfaces of the mirrors are parallel to each other and at a 45° angle to
the axis of the tube. As its name implies, a trench periscope could have
been used in trenches to spot enemies without risking your head. After some
research, I came to the conclusion that not everything was right with this
item. Many military items are usually painted green and that is why the case
has a olive-green color. But I cannot imagine going into a trench and then
spotting my enemies with a black periscope. It would be like wearing a white
suit in a crowd of women wearing black dresses. So why was the periscope not
painted green? We can only guess, but everything has its meaning. It’s
quite possible that the periscope was not meant to be used in trenches at
all. An indication abouts its use can be found in the Hong Kong Museum of
Coastal Defense (http://www.lcsd.gov.hk/CE/Museum/Coastal/) because the same
item is on display there. Was it used from inside a dark bunker to watch the
sea?
The trench periscope
in detail
The pipe, including
the triangular shaped item (which is in fact the upper mirror in a metal
casing) is 44cms long. The wooden handle is 24cms long. So, when completely
screwed together, the item is 68cms long. The upper mirror is mounted on a
sliding iron rod so that the length can be extended to a total of 83cms. The
triangular metal casing of the upper mirror is also important because it
features the well-known prism-shaped AOCo logo. This proves, without doubt,
that this logo was already in use during wartime. The logo probably even
dates back to 1938, although that would be hard to prove.
The "5 x
10°" marking above the logo shows that the trench periscope has a 5x
magnification factor with a field of 10 degrees (at 1000 yards or meters?).
Below the logo, the serial number 8411 is engraved. This matches the serial
number on the case. Finally, below the serial number, there is a very small
box that encloses a difficult to reproduce Japanese ideogram. It is the same
unknown ideogram as on the metal label.
The eyepiece is
adjustable from +5 to –5 and it is the only way to focus the image. When
looking through it, a scale can be seen. This scale, which consists of
vertical lines, has a zero mark in the middle and stretches out to a value
of 50 on both ends. This scale is probably used to determine the size of
subjects at the horizon.
The glass elements and
flat glass surfaces used in the trench periscope appear to be uncoated. It
is common knowledge that Japanese and German manufacturers applied a simple
coating to lenses in WWII. However, it is too easy to state that all
military optical items had coated lenses. It probably was not that common at
all and only used on the most expensive optical items (for instance the
giant ship binoculars made by Nippon Kogaku).
Conclusion
It’s great to
finally come across an AOCo-item that definitely dates back to WWII. Asahi
Optical Co. probably was not a large manufacturer, but this item shows that,
during wartime, the company was indeed producing interesting optical items
for military purposes. This also adds to our knowledge of the company and
its history.
It would be nice to
find more items that date back to WWII or even earlier. There’s definitely
more to be found. If you know about such items, then please share the
information with us!
Acknowledgments
This article could not have been as
informative as it is now without the translation of the metal label by Miss
Megumi Yugeta.