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Gegege no Kitaro Magazine DVD Series, volume 22
Where's Yamada (some background shots)
Kitaro Goods (Glossy photos of various Kitaro yokai)
History of Gegege no Kitaro, #21
Mizuki Collection (Pictures of Kitaro goods that ran in Shonen Magajin)
Interviews or special video sections
Featured supporting youkai page
(Original Art page for Hideigami.)
#42: Hitokuijima (Human-Eating Island, 10/20/68)
#43: Hiderigami (Drought God, 10/27/68)
#44: Geta Gassen (Wooden Sandal Wars, 11/03/68)
#45: Nopperabou (Faceless, 11/10/68)
(Original Art page for Nodzuchi.)
New Yokai Pages:
Hitokuijima (Human-Eating Island)
Hiderigami (Drought God)
Sakabashira (Upsidedown Pillar)
Hitokuijima: Literally, this translates as "Human eater" plus "island". In one sketch from the manga, it's actually a VERY tall monster standing in the middle of the ocean, with just its head sticking out of the water. He seems to be specific to the Kitaro series.
Hiderigami: This is a recognized god from Japanese folklore that can cause droughts. It comes from China, and in one Japanese woodblock print is drawn as having one arm and one eye. In the TV episode, he has one eye but both arms.
Nodzuchi: Another yokai from folklore, but the only information I can find easily on it is the Japanese wiki. It's essentially a gigantic earthworm. In the TV episode, it's sleeping in a huge rock cocoon and is awoken when Hiderigama breathes fire on it. Then it tries to inhale anything that moves because it's hungry.
Sakabashira: "Saka" is "upsidedown" and "bashira" is a pillar, such as what you find in wooden buildings as a central support. Not much on it in English. The main information I can find is in the Japanese wiki entry. One woodblock print seems to show it as an inverted tree. In the TV episode, it started out as a regular support pillar in a shrine building, then turned into a yokai over 100 years.
Maruge: Another Kitaro-specific yokai. This is, simply, a ball made of hair, with eyes, arms and legs.
Nopperabou: This is a class of monsters that don't have faces. The most famous story is of a farmer coming home late at night and finding a woman crying next to a river. She turns around and she has no face. The farmer runs in horror to a nearby home and when he tells his story to the guy in the house, the guy turns around and he too doesn't have a face. In this TV episode, Nopperabou is a yokai that steals the faces of its victims and wears them on its inverted-egg-like head. He's in Tokyo to add to his collection.
(Original Art page for Sakabashira.)
Original Art Pages:
(Back cover: Where's Yamada and the Glossy Photo Kitaro Goods.)
One side note. In Japan, the large glossy photos are called "bromides".