icted ▁in ▁the ▁E do ▁period ▁ka idan ▁( m yst er ious ▁tale ) ▁book , ▁the ▁K ok on ▁Hy aku ▁Mon og at ari ▁Hy ō ban , ▁under ▁the ▁title ▁of ▁the ▁" N ishi oka ▁no ▁T sur ube - otos hi ", ▁where ▁they ▁are ▁y ō ka i ▁that ▁appear ▁as ▁balls ▁of ▁fire . ▁It ▁gives ▁the ▁interpretation ▁that ▁Se k ien ▁also ▁dep icted ▁this ▁in ▁the ▁G azu ▁Hy ak ki ▁Y agy ō '' ▁and ▁titled ▁it ▁" T sur ub eb i ." ▁ ▁Inter pret ations ▁from ▁y ō ka i - related ▁literature ▁of ▁the ▁Sh ō wa ▁and ▁He ise i ▁periods ▁on wards ▁almost ▁always ▁consider ▁the ▁t sur ub eb i ▁to ▁be ▁an ▁atmos pher ic ▁g host ▁light ▁that ▁is ▁similar ▁to ▁the ▁t sur ube - otos hi ▁or ▁as ▁a ▁different ▁kind ▁of ▁y ō ka i ▁altogether ▁from ▁the ▁t sur ube - otos hi . ▁In ▁the ▁Sh ik oku ▁and ▁Ky ush u ▁regions , ▁they ▁are ▁considered ▁to ▁be ▁spirits ▁of ▁trees ▁that ▁have ▁turned ▁into ▁bl u ish - white ▁balls ▁of ▁fire ▁that ▁would ▁d angle ▁or ▁suddenly ▁come ▁down ▁from ▁tree ▁branches ▁near ▁mountain ▁paths ▁on ▁quiet ▁night s ▁and ▁then ▁d angle ▁and ▁repeatedly ▁go ▁up ▁and ▁down ▁like ▁a ▁bur , ▁and ▁it ▁is ▁said ▁that ▁despite ▁being ▁called ▁fl ames , ▁they ▁would ▁never ▁burn ▁the ▁tree ▁itself , ▁sometimes ▁faces ▁of