If it is made in Taiwan, then, to me, it is not a Japanese machine. Further, I believe the reference to Singer 15 clones has been broadened too much. A Singer 15 clone looks very similar to a Singer 15 yet may have reverse and feed dog dropdown features. Often, a generic manual, may be referred to as an HA-1 manual.
Having problems typing on this site, so will leave it as that, for now.