Every four metres the layer is doubled back over itself until two miles

Every four metres the layer is doubled back over itself, until two miles of continuously woven net have been fed into the press frame, a height of eight metres.A hydraulic compressor then starts to squeeze out the extract. After five hours the contents are transferred to a second press, and the process continues for another 10 hours. The four presses each yield 80,000 litres of concentrated soy a day. During the six months of fermentation, proteins in the soy beans turn into amino acids, developing the savoury taste. The starch in the wheat turns to sugar, then alcohol, then acid, each stage in turn contributing sweetness, fragrance, tartness, colour.This is what we mean by fermented soy sauce.

Most of it is pasteurised and bottled, then whizzed off around the world. For home consumption, however, Kikkoman also produces premium extracts (like single malts) that can genuinely be called "superior soy sauce".The three recipes below - Chinese, Japanese and Thai - represent the way the respective cultures use soy sauce.RED-COOKED LEG OR SHOULDER OF PORKServes 6-8A Chinese New Year special, this dish is a must for every feast and is the nearest equivalent to the British Sunday joint. Leg of mutton or shin of beef, cut into large chunks, can also be cooked this way. This recipe comes from Deh-Ta Hsiung's The Festive Food of China (just reprinted by Kyle Cathie, pounds 4.99).1.35-1.5kg/3-312lb leg or shoulder of pork, cleaned4-5 spring onions3-4 slices of fresh ginger root3 tablespoons light soy sauce100ml/4fl oz dark soy sauce3 tablespoons brandy115g/4oz brown sugarMake sure the pork skin is free of bristles and score the rind and meat with a few cuts.Place the meat with spring onions and ginger in a large saucepan, skin side down. Cover with cold water and bring to the boil rapidly, skimming constantly. Add the soy sauces and brandy, reduce the heat and simmer, covered, for 30 minutes.

Turn the meat over, add the sugar, cover, and continue cooking for about 112 hours. Now reduce the liquor by boiling rapidly, uncovered, for five to 10 minutes.To serve: lift out the meat and put it on to a deep serving dish, skin side up. Discard the ginger and the spring onions and pour the gravy over the pork. The meat should be so tender that it can be torn into shreds with chopsticks.MARK GREGORY'S SALMON TERIYAKIServes 44 salmon fillets, 175g/6oz each, skinned and boned1 tablespoon sunflower oil4 sprigs of watercress2 tablespoons grated daikon (giant white radish)For the teriyaki sauce:1 teaspoon caster sugar1 teaspoon sake or dry white wine1 tablespoon mirin or sweet sherry (optional)2 tablespoons Kikkoman soy sauceGrilled salmon tastes fabulous with teriyaki sauce. At Bibendum, there were the supple, fragrant qualities of Denis Mortet's Gevrey-Chambertin "En Champs" Vieilles Vignes (pounds 210) and his sumptuous Gevrey Chambertin 1er cru Lavaux St Jacques (pounds 260).