One knife is the work of at least two people. In Sakai the forging and the edge-making are done by different craftspeople in different workshops, and the trade divides its processes formally into forging, sharpening and scissors; nobody makes the whole object under one roof. The smith produces the shape and the body of the blade. The sharpener puts the geometry on it, and because that is where the cutting angle is decided, the same piece of steel becomes a different tool in different hands.

The workshops are scattered through the city rather than gathered in a quarter. At the Sakai Denshōkan there are displays and, more usefully, a service that will re-sharpen the knife you already own. Nankai and the subway reach Namba in about fifteen minutes, and there is work here in blades and in metalworking generally, so this is that unusual thing: a producing district sitting inside a major city rather than in a valley somewhere. The name Sakai uchi-hamono is a registered trademark held by the trade federation, which is what a district does when there are a great many similar-looking products elsewhere.

A divided trade cannot function without someone holding it together. Orders have to be distributed between smiths and sharpeners, and the results have to come out consistent enough that a customer buying two knives a year apart gets the same thing twice — so the capability of the district lies in the coordination as much as in any individual's skill. Behind a single finished knife there are at least three sets of judgements, only one of which is visible in the steel.