Kaygetsu is not only one of Silicon Valley’s best Japanese restaurants, it’s one of the best restaurants period. The restaurant specializes in kaiseki-style cooking, a visually stunning, technically demanding school of Japanese cuisine served in multiple courses.

But that’s not what this review is about; it’s about sushi, really great sushi. In a corner in Kaygetsu is a six-seat sushi bar presided over by Kaygetsu’s co-owner, Toshi Sakuma. This restaurant within a restaurant is one of Silicon Valley’s premier, if lesser-known sushi destinations.

Before opening Kaygetsu, Sakuma and his wife, Keiko, ran a popular sushi restaurant nearby, and Sakuma’s skills as an itamae are as sharp as the eight-inch knife he wields behind the bar. He makes sushi and sashimi for the fish courses of the kaiseki menus, but to get a real taste of his talents, one should pull up a chair and order right from him.

The selection of fish in the Hoshizaki refrigerated case is relatively small and standard, with a few seasonal additions. What makes the fish unique is its incredible freshness. It’s simply impeccable. 

Sakuma, a short man with close-cropped gray hair, works silently and quickly. He’s not the chatty type. Watching him deftly slice off pieces of fish or form a rice pad with astounding speed and dexterity is a real pleasure. Not a motion is wasted. Everything he does is precise and purposeful—and delicious.

Sakuma’s fish not only looks perfect, he serves it in the perfect amount: just enough for one or two bites. A big, sloppy slab of fish would detract from the ethereal experience of Sakuma’s sushi craft.

Lunch is a great time to sit at the bar. It’s not as crowded as dinner, but with just six seats, calling ahead to make a reservation is helpful. In spite of its location in a shopping center across from a gas station, Kaygetsu is a high temple of Japanese cuisine. Located off Sand Hill Road, Silicon Valley’s venture capital row, the restaurant attracts a dedicated following of high-tech executives, which makes for some great eavesdropping between bites. But it’s the food, not the Silicon Valley shoptalk, that distinguishes Kaygetsu.

The sushi lunch ($28) is a good place to begin: 10 pieces of nigiri sushi and a bowl of excellent miso soup. You get to choose what kind of sushi you want, but I defer to Sakuma. He knows what’s best each day. It’s nothing you haven’t had before: salmon, amberjack, flounder, white tuna, yellow tail, shrimp and snapper, but the texture and flavor of the fish, especially the salmon, flounder and white tuna, are astounding. The fish is so rich and silky, it’s as if it had been smeared with butter. I also liked the tamago, or omelette. The egg is beautifully layered with a marbled appearance and is just barely sweet.

Sakuma uses fresh wasabi instead of powdered, and the difference is dramatic. The real stuff has a pure, pungent heat that really sets off the fatty, rich fish.

Sashimi and nigiri (fish on rice) are the best showcases of Sakuma’s skill, but it’s worth ordering a few rolls to round things out. Kaygetsu serves a special brand of handmade nori from the Ariake Sea and claims to be the only restaurant in Northern California to do so. Although good, it didn’t stand out for me. But filled with the custardlike sea urchin or quail egg–topped salmon roe (egg on eggs, so to speak), it makes for a great roll ($9).

I don’t know about you, but after eating a meal of premium sushi, I feel a bit high—euphoric even. All that raw fish gives me a protein buzz. After leaving my seat at sushi master Sakuma’s bar, I was downright intoxicated.