That one isn't a clone, it's somewhat of a copy of an old Necchi BU. A clone is a copy of an old black straight stitcher. This is a 15 class clone:
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As far as dating a Japanese machine, it's not easy. There are no searchable records. The only ways I've found to date one is to find the original sales documents with the machine, or search old magazine ads or catalog pages. I can guesstimate vintage Brothers going by features because I know when my mother bought hers and I have some old magazine ads.
Cari