This appears to be a mounted bead, probably from a Mandarin hat, from sometime in the Qing Dynasty. Jamey
After the end of the Qing empire in 1912, court artifacts from necklaces and hats seem to have been popular for conversion into trinkets such as servant bells, canisters, and jewelry for foreigners. The style of cloisonne work on these beads matches Fran's "lantern" beads necklace.
http://www.beadiste.com/2015/01/puzzling-evidence-rare-deco-chinese.html
I own the 3 beads from the auction photo in the blog article, and posted about them here:
http://beadcollector.net/cgi-bin/anyboard.cgi?fvp=/openforum/&cmd=iYz&aK=535220&iZz=535220&gV=0&kQz=&aO=1&iWz=0
When you say "sagemono" you are saying netsuke ensemble. Which means this is intended for usage as an ojime. I say not.
This is an adaptation with a perforation which has been altered with a collar which is neither Chinese nor Japanese.
featuring these beads as pendants.
After nearly fifty years of experience with antique Chinese beads, having handled about five or six graduated necklaces with this type of enamelwork, and fewer than twenty loose ones (they are scarce)…
I find this type of enamelwork is rarely found in Mandarin Court Necklaces. But more often in beads made for fashion in the 1920's and 1930's
The way to rule out the possibility it may be from a MCN, is to measure the bead. While the Mandarin Court Necklace is always the same length, the size of the beads in a MCN varies just slightly.