Funayūrei - The ghosts of those who died at sea. These ghosts are sometimes depicted as scaly fish-like humanoids and some may even have a form similar to that of a mermaid or merman.
Samurai Ghosts - Veterans of the Genpei War who fell in battle. Warrior Ghosts almost exclusively appear in Noh Theater. Unlike most other yūrei, these ghosts are usually shown with legs.
(pronounced shokujinki in modern Japanese) are the spirits of greedy, selfish or impious individuals who are cursed after death to seek out and eat human corpses.
Ikiryō- "a manifestation of the soul of a living person separately from their body"
In Japanese folklore, not only the dead are able to manifest their reikon for a haunting. Living creatures possessed by extraordinary jealousy or rage can release their spirit as an ikiryō, a living ghost that can enact its will while still alive. The most famous example of an ikiryo is Rokujo no Miyasundokoro, from the novel The Tale of Genji.
Obake Yūrei often fall under the general umbrella term of obake, derived from the verb bakeru, meaning "to change"; thus obake arepreternatural beings who have undergone some sort of change, from the natural realm to the supernatural.
When looking at typical kaidan (roughly translated as old fashioned ghost story), this does not appear to be true. Yūrei such as Okiku haunt a particular place -in Okiku's case, the well where she died-, and continue to do so long after the person who killed them has died.
Zenshoan(全生庵) Temple in Tokyo, Japan is known for its collection of yūrei paintings, known as the Yūrei-ga gallery. The 50 silk paintings, most of which date back 150 to 200 years, depict a variety of apparitions from the forlorn to the ghastly.
The scrolls were collected by Sanyu-tei Encho(三遊亭円朝), a famous storyteller (rakugo artist) during the Edo era who studied at Zenshoan. Encho is said to have collected the scrolls as a source of inspiration for the ghostly tales he loved to tell in summer.