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Gegege no Kitaro Magazine DVD Series, volume 19
(Original art: Mouryou)
Where's Yamada (some background shots)
Kitaro Goods ("Magic Prints" - Showa-era laminated character sheets)
History of Gegege no Kitaro, #18
Mizuki Collection (9 Shonen Magajin covers featuring Kitaro)
Interviews or special video sections
Featured supporting youkai page
#30: Akuma Berial (Demon Berial, 07/28/68)
#31: Mouryou (Goblin, 08/04/68)
#32: Youka (Bewitching Flower, 08/11/68)
#33: Sazae Oni (Turban Shell Demon, 08/18/68)
DVD Easter egg: Walking Geta
(Original Art: Sazae Oni)
New Yokai Pages:
Karasu Tengu (Tengu Crow)
(New Yokai: Akuma Berial)
Akuma Berial kind of looks like a devilish Shakespeare. He's accompanied by a crow version of a tengu spirit.
Mouryou generally refers to "many spirits and goblins", but in this case seems to be just one grass-covered Tottoro goblin.
The "you" in "youka" is the same as that for "youkai", which is the group of monsters and/or creatures that this TV series revolves around. By itself, "you" translates to "bewitching", "attractive" or "calamity". "ka" is "flower". Because the youka entrances its victims before destroying everything, all three meanings for "you", plus the sense of "youkai" can apply here.
"Sazae" translates to "turban shell" and its real body does have a seashell for a head. Normally, though, it disguises itself as a troll with hair covering its face and its eye located at the end of its tongue, with its body covered in tattoo-like barnacles.
Original Art Pages:
(Back page: Where's Yamada and Kitaro Goods.)
One thing I haven't mentioned yet about the earlier DVD volumes is that the individual chapters in the root menu are occasionally messed up. There have been several cases where selecting Part A of an episode (the first half of the episode starting right after the opening credits) causes Part B (the second half, right after the break title card) to play. And, on one DVD selecting individual chapters caused my player to completely lock up. So, there is something of a quality control problem with the main menu programing.