Illustrations from the 1948 children's comic The Magic Underground Castle (魔の地中城)
by another 50 Watts fave, Rokuro Taniuchi (1921–81)
This was a surprising find from my many blind searches in the picture book database of the National Diet Library (click that to see the whole book). Roku is one of my favorite illustrators from any time and any place, and I had never heard of this comic, which has a very different feel from his later work. This is the only Roku book in the database (luckily there are seventeen by Takeo Takei).
Some of Rokuro Taniuchi's books have been reprinted and are available from amazon.co.jp.