When reading the Yamachichi, the most important thing is not to overinflate this yokai as a "well-known local legend." The core material is the "Ehon Hyaku Monogatari", which tells of its transformation from an old bat to a Nobusuma and then to a Yamachichi, alongside the strange effect of sucking sleeping breath. Precisely because it is a yokai with scarce materials, accurately placing its appearance, actions, and conditions makes its outline clearer.

The appearance of the Yamachichi is a mountain beast resembling a monkey with a pointed snout. It does not shapeshift into a human like a fox or a tanuki, nor does it lure people with human speech like a Yama-uba. It remains a beast, drawing near to the breathing of a sleeping human. Breathing is the entering and exiting of life, and sleeping breath is the sound of defenseless life. Because the Yamachichi sucks that sound, its terror lies not in claws or fangs, but in the sensation of life being drained in the vulnerable gap of sleep.

However, the tale of the Yamachichi is not a simple blood or spirit-sucking story. If someone is watching, the person whose breath is sucked gains a long life. If no one watches, they die the next day. This condition is mysterious; the eyes of a third party determine whether the anomaly harms or saves the human. The structure where the monster's power is reversed by being seen is also the charm of Hyaku Monogatari (Hundred Tales) style storytelling. The triangular relationship of the person in the bedroom, the sleeper, and the watcher establishes the small narrative of the Yamachichi.

Its location is said to be Oshu, but Oshu here is a broad regional name and should not be shrunk down to a single modern point. Using Mutsu Province as a receptacle for the ancient place name is to indicate the scope of Oshu found in literature, not to assert it as solely a yokai of Fukushima Prefecture. Rather than a precise point on a map, the Yamachichi is a yokai spoken of within the sense of distance of "the mountains of Tohoku."

If connections are to be drawn, it is closest to the Nobusuma and the Satori. The Nobusuma appears in the text as the preceding stage of the Yamachichi, supporting the Yamachichi's position as an aged form. The Satori shares an interpretive intersection, as the text states, "Deep in the mountains, this is called satori-kai," but the mind-reading Satori and the breath-sucking Yamachichi are not identical. By lining them up while maintaining this difference, we can see the subtle divergence concerning breathing, thinking, and sleeping among the beast yokai of the mountains and fields.