WWII Japanese Artillery Plotting Boards

[BOUGAINVILLE]

Here are two very interesting WWII items for Artillery Fire Direction and they come complete with instructions.

The first one is I presume a graphical firing table and the second one I think is a range deflection protractor for computation of direction to be sent to the guns.

I would be grateful if anyone has any interesting information to add about them. :hmmmm:

Cheers,
BOUGAINVILLE