You know I'm not sure I can put it in to words. He just seems to hit an unusual spot. His characters tend to have a certain distance and yet an intimacy with each other that seems uniquely Murakami. There's a wide space that weaves between the characters and yet it carries so much weight. His novels are almost philosophical when it comes to analysing human relationships and the grind of daily life for the troubled soul.
Add a slight tint of the surreal, jazz, cats and sex with weird women and a dash of mystery and BOOM, there you go.