thanks to you both for your comments! @heinz...one explanation i'm familiar with is that because food is sometimes placed in front of these statues as an offering, the bib is present to catch the statue's drool in response seeing food without being able to eat it. another explanation i've heard is that because these statues are usually known as å°èµ (jizo), and the main responsibility of jizo is to look after children (including unborn and aborted babies), the bibs, which retain the smell of the baby(ies) in question, allow the jizo to identify (by the smell) and rescue thebaby(ies) from hell. i'm sure there are many other explanations, too, but those are the two with which i am familiar.