How does one do this? My fork has Ishiwata impressed into it, and below that "1" and then a "." and then "J" above those is the circular logo, looks like an SIJ at an angle? I am wondering if there are any other ways to tell if you have 022 019 etc? I have searched but did not find then specifically. Thanks.
JIS is just the Japanese Industrial Standards organization, means that the manufacturer complies with those standards. As far as ID-ing a tubeset without a decal present: the best you can do is research the specs for your specific frame (search old catalog scans at bulgier.net for example) or try comparing the weight of yours to a known Ishiwata frame of the same size.