Tsurubebi

The figure of the tsurubebi appears in Edo-period illustrated yōkai compendia such as Toriyama Sekien's Gazu Hyakki Yagyō and is linked in kaidan collections (notably the Kokon Hyaku Monogatari Hyōban) to tales titled Nishioka no Tsurube-otoshi. Regional traditions in Shikoku and Kyushu conceptualize these lights as spirits of trees transformed into luminous balls; modern commentary sometimes offers naturalistic explanations (for example, bioluminescent organisms in fungi and humus on branches) alongside the older supernatural framing. Sources treat tsurubebi as part of the broader class of onibi/chōchinbi atmospheric ghost-lights rather than as a household or ancestral deity.

Folklore descriptions characterize tsurubebi as balls of fire or bluish-white balls of light that dangle from tree branches or suddenly descend from them. Regional accounts report they oscillate or bounce ("dangle and repeatedly go up and down like a bur") and, in some stories, appear to show human or animal faces within the flame. Toriyama Sekien included an illustration titled "Tsurubebi" in Gazu Hyakki Yagyō; the compendium provides an image-labeling of the phenomenon but the supplied sources give no extended explanatory text from Sekien himself.

Tsurubebi function primarily as luminous, uncanny phenomena encountered on quiet mountain paths at night. They hang from or descend from tree branches and display motion such as dangling and bouncing. Multiple sources stress that although they are described as flames, they do not burn the trees they appear on, indicating a non‑combustive, spectral quality. While some literature links the name to the related tsurube-otoshi tradition (in which a tsurube-otoshi is said to drop from trees and attack), the supplied sources distinguish the ball‑of‑fire tsurubebi motif from the explicitly aggressive dropping-attack tales of tsurube-otoshi; attack behavior is attested for tsurube-otoshi in kaidan, not definitively for tsurubebi in the provided material.