Antique cloisonne enamel magnifying glass, Japanese, cranes in central panel with flowers blue enamel over copper early 1900s

Great cloisonne enamel magnifying glass, enameled on all sides of the three pieces, Japanese, first part of the 20th century I believe, though there are no marks on the piece, or in the pattern on the back that I can discern. It's 2.5x2x.5 inches closed. The fact that it's not "perfect" (see the enamel skip on the back side of the front panel?) makes me wonder if it wasn't made as a domestic piece, rather than for export, given that it would be fine for use by anyone and wouldn't be discarded out of hand. Two shades of blue enamel make up the fields into which the flowers and cranes are set; you can see said shades on the photo of the reverse. Has a chain loop for attachment to something more secure, or it could be threaded through the central rivet that holds the three panels together (slightly wobbly, but secure, and any local jeweler would shore it up for about five bucks with a new copper rivet probably). A nice, and unusual, bit of cloisonne enamel, and comes in handy, too!