To summarize:
 
	 
 
	1) it’s definitely Ono no Komachi in old age rather than a Shojo.
 
	 
 
	2) The characters appear to be the ones identified by Piers, but the signature is not included in any list of netsuke carvers.
 
	 
 
	3) the top-down hole is not what you would expect in a netsuke, but the item seems too large for an ojime (i.e., the bead that is positioned on the cord between the netsuke and the object that hangs from it).
 
	 
 
	So this piece remains a bit of an enigma to me. Based on these pictures I would generically place it in the 19th century, but I can’t say exactly what it is or whether it has been tampered with at a later stage.