Layout. Zashiki Onna is a masterclass in how layout can carry an otherwise straightforward manga. While I found the story a traditional urban legend with a distinctly Japanese flavor, the suspense that Mochizuki injects into the work through clever scripting and shot composition pulls the viewer into Hiroshi's plight.
While initially put off by the otherwise ugly artwork, I found the tight plotting and grim end worth the ride. Any fans of horror and suspense should check out this quick little number if merely to see how powerful suspense can be developed in a comic book. Just be sure to read this one as slowly as you can bring yourself to consume it. Speeding through each page won't give you enough time to let the atmosphere sink in.