Two brothers wearing bunny suits hop on a phallic train and travel to a mysterious underwater brothel.
The story is very surreal and deranged in an Alice-in-Wonderland kind of way. The art style is quite original and seems influenced by European comics, in particular the likes of Jean Giraud.
Ryuguden is a unique roller-coaster ride of a story. Two young brothers clad in rabbit suits are invited aboard a strange train and are whisked away to a mysterious underwater castle. The plot never seems to slow down from there, only building endlessly upon itself. The story borrows heavily from the legend of Urashima Tarō but quickly morphs it into something all its own, exploring coming-of-age themes as well as mankind's self-destructive relationship with technology and the environment. The pleasure is in the ride, and it's hard to go into details here without spoiling all the twists and turns, but suffice to say it's a surreal blend of fantasy and science fiction that I found extremely satisfying.
But the thrill of Ryuguden is not just in the wild, breakneck story; the book revels in the art of comics-making. Mastunaga's linework and character design is masterful and varied throughout the book and Ryuguden is littered with jaw-dropping panels. Mastunaga employs a hybrid drawing style somewhere between the ligne claire minimalism of Moebius and the rubber hose anatomy of early American cartoons, and the characters careen around a starkly constructed environment that grounds all the fantastical action in the physical space of the castle. It's a combination that really allows the action and inventive character designs to shine. But gritty detail erupts here and there as the story progresses, punctuating the dreamy, fairy tale atmosphere with gruesome body-horror and tightly choreographed fight scenes. Nearly every panel across all three volumes is a visual delight.
I don't believe this book is currently licensed in English, but the fan translation available online (as "Ryuuguuden") does a capable job with Matsunaga's straightforward dialogue. If you like your manga a little off the beaten path, Ryuguden is highly worth seeking out. (Thanks to Carta Monir for the recommendation on twitter.)