The science of slicing
When Hirohisa Koyama brought his team of chefs to the Manoir aux Quat'Saisons earlier this summer he brought more than the refinement of classic Japanese Kaiseki dining, the subtle dishes that precede the Zen Buddhist Tea Ceremony. He brought a lifetime's experience of exquisite knifemanship.
Japanese chefs' knives are the work of sword-smith families - Shoudai Masayoshi, Masamoto, Aritugu - knife makers who once made the blades of samurai warriors. Today they still use the same techniques - beating out and folding the steel until it has as many layers as puff pastry.
Like swords, the deba, banno and sashimi bocho - the names of different types of Japanese knives - are one-edged and razor-sharp.
The technique of wielding them owes much to kendo, the disciplined craft of sword fighting. The key difference between the Japanese and Western way of cutting is that the wrist remains locked and stiff throughout. The elbow too stays firm. All the motion hinges around the shoulder.
According to Koyama, the way a chef cuts influences the way the way an eater will perceive flavour. "Cutting", he explains, "is the main thing. Cooking only comes after. If you don't cut well you don't finish well."
With sashimi, raw fish, the taster's first response when putting it in his mouth is how it actually feels on the tongue and palate. If the surface of the slice isn't perfectly smooth, it won't taste right.
Achieving the ideal texture depends on the sharpness of the blade and the skill of the person wielding it.
The first thing a Japanese chef does to prepare his knife is, in fact, the last: he sharpens the knife after each day's work. Here, the object is to avoid any jaggedness, which would lead to the edge sawing the food rather than slicing it.
A well-honed blade is actually harder to cut with than a jagged one, but it gives a surface, especially when cutting through fish flesh, that is finer and more brilliant. Anything less squashes and damages the finish and spoils the flavour.
Cutting, a little like our carving, is a combination of the angle at which the edge of a knife comes into contact with the object and the speed (or rather, rhythm) with which it is pulled away.
The long, straight blade of a sashimi bocho is there for a purpose. Too much pressure and it doesn't shave.
Koyama's commis, some of whom have worked with him for many years, all know how to handle their kitchen knives. But they bow to his craftsmanship, recognising that he does it better than they can. They watch him at work and aspire to reach his level of mastery.
