Whether you need to adjust action or pickup height, a ruler is an absolute must-have because even if you tweak all those settings by ear and feel, it might still be useful to know what your preferences are. According to one reviewer here, these rulers are made by Shinwa in Japan.
However, even though the one I received did indeed bear Shinwa branding, the country of manufacture was specified as China. To me, it is not an issue, but I wanted to share my side of the story, as it were, for the benefit of those who regard these matters as important.
The ruler is stiff and well made, despite a few superficial scratches. Some of its edges are not perfectly even, which I consider acceptable for my purpose and in this price range. After all, I am going to use it to measure guitars, not spacecraft. Also, have in mind that I am judging from the point of view of an absolute perfectionist, so, in spite of all of my criticism, I would buy one again if I needed.