In sushi instructional videos -- how to make your own -- the sushi chef always starts by clapping his hands twice and saying "Happy sushi." Is this little ritual supposed to inspire the fish fillets to be thrilled about their forthcoming digestion? Well, actually, it's meant to remind the sushi chef to take joy in his art. And creating sushi is a fine process. The sticky rice has to be cooked, then fanned until it's cool (or it will become lumpy), and seasoned just so with sugar and vinegar. Then it should be shaped the size of two fingers (the same measurement as a shot of vodka in your tonic). But the real difficulty lies in slicing the raw salmon, tuna, yellowtail snapper, and mackerel, to name just a few of the most popular fishes. The knife has to be sharp as a genius' intellect, the cut at an angle but not unevenly, the slices thick but not chewy. Yama's sushi chefs are clearly clapping their hands, because their sushi is nothing short of art. The only difference between their sushi and works of art, in fact, is that one is meant to be eaten, the other to be framed.