It's time, in short, to learn your santoku from your gyutou, your yanagi from your usuba.

Santoku is the most common term being used (and misused) to describe a new family of multipurpose knives based on Japanese designs. But the subject is a bit more complex than that — OK, a whole lot more complex, if you're a fanatic, as some chefs have become.

But we'll try to keep this introductory lesson simple.

In western Europe and the United States, the standard everyday kitchen knife is the 10-inch chef's knife — a long, medium-weight knife with a blade shaped like a very elongated triangle, sharpened from both the right and left sides to create a sharp "V." Other knives, such as short-bladed parers, serrated bread slicers, and flexible boning knives play a role. But most Western professionals consider the chef's knife an extension of their arms.

In China, the cleaver plays a similar role, with skilled chefs able to turn this seemingly unwieldy tool to even the most delicate tasks.

In Japan, however, there is a trio of common knife types, any one of which can become a chef's favorite tool, depending on how they were taught, and by whom. The three are: lightweight vegetable knives called santoku, usuba or nakiri; heavier chef's knives known as gyutou or deba; and long, slim slicers known as yanagi, sujihiki and by other names.

"In Japan, we're really trained to use one type of knife for mostly everything," said Japan-born and -trained chef Hiroshi Fukui of Hiroshi Eurasion Tapas at Restaurant Row. "If it's a small thing like peeling vegetables, we're not going to change the knife for that. We're taught to use whatever we have."

Grant Sato, chef-instructor at Kapi'olani Community College, who teaches both knife skills and Asian-style cooking, loves the Misono-brand santoku he bought in Japan for $450 some years ago. It is the classic Japanese all-purpose vegetable chopper, with a round handle of long-lasting magnolia wood and a single-bevel blade of carbon steel. He is as careful with it as a mother with her baby, faithfully washing it clean after every use, drying it thoroughly, and literally tucking it into bed — wrapped in a silk cover and placed inside its own case.

Two features of Fukui and Sato's knives characterize classic Japanese cutting tools: the single bevel and the carbon-steel blade.

• The single bevel — an angled blade edge sharpened only from one side — is the key difference between a classic Japanese knife and newer fusion styles. Chefs say this angle has the advantage of causing the food to slide up and out from the blade, rather than sticking to it, so that sashimi, for example, shingles out readily into a beautiful display. Fukui says single-bevel blades allow you to slice more thinly, and the cutting edge is smooth and shiny, an aesthetic difference valued in Japan.

• Carbon-steel blades. Carbon-steel blades take an extremely thin edge, slicing "like buttah." But carbon steel has its drawbacks. The blades need frequent sharpening and therefore wear down more rapidly (though a good knife is going to last many, many years). The ultra-thin edge is more delicate and brittle, and it can become pitted and uneven readily if mistreated. And Sato said a carbon-steel blade will rust literally within hours if it stays wet. "This is not a knife you're going to just slam into the butcher block," he said.

Japanese single-bevel knives are most often designed to be used by the right-handed (left-handedness traditionally had a negative connotation), but you can buy left-handed versions now, Sato explained. And these knives are ideal for the Japanese cutting motion, he said, which employs a down and back (toward the cutter) direction. (Western-style cutting is more up and down.)

The latest trend blends features of both East and West: They are double-bevel knives made of high-carbon stain-resistant steel with Western-style ergonomic handles. Fukui said younger chefs at his restaurant have taken to these. Purists say you get a longer-lived edge at the expense of truly thin and smooth slicing.

You can literally spend whatever you want on a Japanese knife, from as little as $30 for traditional, single-bevel knives of everyday quality to the stratosphere of four-figure prices for hand-made pure steel knives imported from Japan. For a good-quality knife, either Japanese or Western style, you'll have to budget at least $100.

There's one reason in particular for Islanders to pay attention to the Japanese knife trend: These knives are often shorter of blade (7 inches is common for santoku, 8 inches for gyutou), lighter of weight, and more ergonomic of handle than their European counterparts.

For years, my everyday chopping and slicing tool was a 10-inch French-style chef's knife made by Henckels in Germany. I kept it well-sharpened and away from the dishwasher, but it was overlarge for my stubby-fingered hands and an extended bout of chopping left me with a fatigued wrist and arm.

Then one day I was watching a chef in a sushi bar cutting impossibly thin slices of carrot at a pace that made my eyes go blurry. And I knew what I wanted: a shorter, lighter knife with a thin blade.

Today, my everyday knife is a rather attenuated but well-balanced instrument with a molded handle that comfortably fits my hand. It works very well for most purposes. The only time I pull out a different knife is when I'm boning meats or hacking through an entire carcass.