basic sushi

Sashimi technically isn't sushi. Sushi uses vinegared rice, while sashimi is simply raw sliced fish. I felt it was necessary to include it, however, because sashimi is often eaten at the beginning of a sushi meal, and I actually prefer to eat it over sushi. There are two regular cuts when cutting sashimi, the angled cut and the flat cut. Most fish is cut flat for sashimi. Holding the fillet in one hand, cut 1/4 to 1/2 inch thick.

Select the best fish you can find. If you're not using a sashimi knife (I don't have one yet myself), it may be helpful to place the fish in the freezer for a few minutes to firm it up a bit. Run your fish under cold running water, rubbing the surface slightly. Using paper towels, pat (do not rub) the surface of the fish dry, then place it on a clean cutting board. It's now ready to cut for sashimi.

Here I'm cutting tuna using the angle-cut method. Using a rectangular piece of fish, cut a triangular shape off one end. You can use this for pieces in thin rolls or to make a minced fish for gunkan or hand rolls. Hold the knife at an angle, and slice off thin pieces. This is the perfect way to cut neta (toppings) for nigri.
Here's some flat cut tuna, about 1/4 of an inch in thickness. Flat cut fish allows for thicker pieces, preserving more of the texture of the fish.
Here's some angle cut tuna. With the angled cut, you're able to expose more surface area. In foods, flavor is most evident by exposing more surface area. While it's not the common procedure, I prefer to cut finer tuna thinner to experience the flavor rather than the texture.