Color of brown enamel - have never seen this in any Chinese cloisonne bead

Little kidney-shaped motifs - never seen in any Chinese cloisonne, but can be found in Japanese pieces

Overall composition - have never seen anything as abstract and borderline geometric as this in Chinese cloisonne beads

Trefoil mon appear in Japanese art, of course, but the trefoil motif is not common in Chinese motifs (that little yellow vase is a typical example).

Hole size - very large, ample to accommodate inro cords

Hole rim - Chinese cloisonne beads with rings around the hole are often double, or not as thin and precise and exactly on edge as this one. Likely because in Chinese beads the rim wires are applied on the surface, whereas the metal hole rim in this bead is actually the edge of an interior tube running the length of the bead. Have never seen a Chinese cloisonne bead with this type of construction.

Metal appears a bit oxidized by age, not chemicals.