Convenient when you want to get a little length. It is hard to see if it is a general ruler, and if it is a plastic it is fuja nya. With this it is understood by the feeling that it caught at a glance. I am saved for the presbyopic eye.
First of all, the JIS standard itself is quite rough. Even if it falls within the JIS standard, straightness is unrelated to the extent that it can be seen by appearance. Both 150 mm and 300 mm are rough. Light will leak if you wear it in accordance with the bending ruler with exact straightness. The length of the Showa 's straight length and turning scale was far more accurate. Japanese manufacturers Please do their best.