Nekomata and bakeneko are frequently used as if interchangeable, and a great deal of popular writing on Japanese folklore treats them as simple synonyms, but the more careful folkloric distinction, where it is drawn at all, separates them along two lines: bakeneko is the broader umbrella term for any supernatural cat, defined mainly by longevity and general shapeshifting ability, while nekomata is specifically the variant with a forked or split tail, a physical marker bakeneko does not require. Bakeneko is also more consistently the household variant, while nekomata carries the older association with mountain wilderness, though later sources increasingly apply both terms to a housecat grown old and strange.
This atlas records the two under a shared Cat Spirits heading rather than merging them into one entry, on the same reasoning it applies elsewhere to closely related regional or terminological pairs: the forked tail, the mountain-versus-household setting, and the somewhat different tone of the stories attached to each, corpse reanimation and human speech clustering more heavily around the nekomata specifically, are distinctions folklorists studying yokai continue to draw even when popular usage collapses them, and an atlas recording the tradition should preserve a distinction its own sources still make rather than pre-emptively erasing it.