Hello! I'm working on a presentation for Youmacon at the end of the month about Mononoke and its embodiment of Japanese ghost stories (kaidan) amd many of your resources have helped me deepen my understanding of this amazing anime. So, here's a question I haven't really been able to figure out: Why was a hinezumi chosen as the mononoke for the second movie? As best I can tell it has no relation in lore at all with childbirth, while the movie stressed this relation constantly. Any insight or ideas you might have would be super helpful! (Beyond it being a fire element yokai to match with the water element of karakasa, of course). Thank you!
To answer this question, we need to first examine the symbolism and significance of the common rat instead of the Hinezumi. In the original Ayakashi series, there was a throwaway line after the Sakai entourage got spooked by scurrying rats - that these rodents are an omen of Mao bearing many children. Indeed, rats in real life multiply quite quickly. However, from a universal standpoint, they are generally considered pests which need to be exterminated.
The ochuro have the sole purpose of bearing heirs for Tenshi. Although merchants sell journals and trinkets featuring rats to low-ranking maids, within the upper echelons of the ooku there is an underlying mindset: while commoners pray for ochuro to be blessed with the fertility of rats, they do not want a "rat" to taint the royal bloodline.
As for why it is the Hinezumi specifically, I have a few thoughts. The Omizu-sama faith demands its disciples to discard what is most precious to them and drink water drawn from the well daily. For many women, what's precious to them is a material belonging. For some ochuro, it is motherhood which must be discarded out of duty.
The abortifacient is also a liquid. When an expecting mother drinks it, they are "discarding" their motherhood much like one douses a fire, or, as the elder Otomo puts it, the "spark". Words hold power, so multiple snuffed out "sparks" may combine into a flame. Rat + flame = Hinezumi.
