I have an antique Javanese mask that I purchased from Japan of all places. Its got exactly this same red pigment paint, and that has flaked in a few places to reveal a lighter pigment of the same color below. See the link to it below. The one I am referencing is the “urban” version. Everything about mine, the age/insect activity,dryness of the wood, patina, cracking in the paint, style etc, all points to this being ca 1900-1930 in my opinion. I suspect the latest in your blog fits squarely into that same time period. Hope all is well. Book looks like it has come along! Nate, 816