Since beforeKill Bill Japanese knives have been cool. Hell, I’m obsessed with Japanese cabinet-making tools. They are very beautiful and sharp.
Now everything Japanese is going mainstream with chefs. As Harris Salat says in Salon:

“And not just those of the cooks. Since the mid-’90s, Japanese knives have become de rigueur in professional kitchens of all stripes — edging out, so to speak, German and French blades. As top chefs like Thomas Keller, Charlie Trotter and Jean-Georges Vongerichten discovered Japanese knives, home cooks began to follow, and in the last five years sales have exploded. Even the enterprising Rachael Ray now hawks an “East/West” blade based on Japanese design.

“They’re perfectly engineered,” said legendary four-star chef David Bouley. As he pulled out blade after Japanese blade — he owns 50 — he explained that these knives cut through the cells of ingredients so cleanly and precisely that food oxidizes more slowly, and tastes better as a result.”

And there’s more”

“Japanese carbon steel derives from techniques originally developed to produce steel for samurai swords. Its exceptional hardness lets you hone an incredibly sharp edge on the blade.

Shape is also critical. Japanese knives come in two broad styles: Western and traditional. Western looks like the double-edged knives we know. A gyutou is what we’d call a classic chef’s knife — this is the one American chefs typically buy. Traditional Japanese kitchen knives, on the other hand, come in three main shapes: yanagi, usuba and deba. The yanagi, which looks like a long willow leaf, is for slicing raw fish. The usuba has a wide rectangular blade for cutting vegetables. The deba is a heavy blade like a thick chef’s knife, for portioning fish and chicken.”