Korean Ruler Brass and Birch(?) 10' Folding Ruler or Measure?

Have had this for a while - I believe the marking is Korean - It is about 10 feet long in 17.5" x 1.5" sections. Both sides are marked 100 thru 250 in 10ths - visible side marking spans about 6'8" and the verso spans 2'4".

The numbers/markings were likely set with a Leroy-type lettering guide, which have been around since about 1940, then etched and filled with white paint. I see no other markings.



Any clues??? Any help appreciated

 

Is that first picture the box it came in or what?

 

No, BG - just a picture of the lettering instrument - I wasn't sure when Leroy lettering came into being - I don't think it predates that.

 

Ah. Well, you've got yourself a super secret very specialized measuring device - purpose so secret, if they tell you what it's for, they have to silence you.

Letter does look Korean to me, but then it might be modern Japanese too.

 

LOL - If only someone is brave enough to translate!

Can't figure it out! I thought of a depth measuring device, but didn't get far with that and doesn't explain the two scales

It's 10 feet long and not especially wieldy.

Any suggestions on what to call the folding mechanism? It's not a scissor or swivel, which is what most folding rulers are.

Thanks BsG!

 

Accordian?

 

Japanese.

The first line tells us this was associated with the Type 15 Gun Camera, which was used mainly for training.

The second line I roughly parse as "Shooting -- Success -- Examine -- Slide Projector Use -- Distance Measure Ruler (Metre)."

I don't know much about how the Japanese trained aerial gunners, but I assume the films taken by the camera in training were later projected on a screen, and this ruler was used to determine how far off target the aim was.

Add:

I now see that on the overall photo there's an additional mark on the ruler to the far right that marks the optical center. Again, I don't know much about projectors, but I'd assume this mark was used to set up the screen at the proper distance from the projector. This might explain why the ruler is marked on two sides: one for setting up the screen at the right distance, the other for measuring aiming accuracy on the images. Presumably you'd need to set the screen at the correct distance from the projector to get consistent readings when measuring aiming accuracy.

 

Well, that was unexpected!

 

Cool Widget
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Still haven't seen a "type 15" model, but close and not quite sure how they use the ruler + projector, but:

Thumbs up, kh1889!

 

Got it... or close enough, anyhoo

 

Springfield Arsenal might have something useful to add, but he's unlikely to look at a thread on Korean rulers unless you contact him.

 

@springfld.arsenal

Come check this out, please!

Maybe that'll work

 

Hi, not sure how the ruler was used but I'll sleep on it and see if the Sandman has any thoughts.

 

Thanks, @springfld.arsenal - i kind of have a gist of it from kh1899,but anyting you can add is appreciated...

 

kh explanation sounds great to me.

 

Thanks @springfld.arsenal

In a perfect world, I'd find some old images of said classroom in action, or maybe a manual with diagrams showing how to use it...

Maybe I'll contact the auction site or WWII forum.