Scarcely less important in Japanese eyes than the chiselling of the decorative design itself is the preparation of the field to which it is applied. There used to be a strict canon with reference to this in former times. _Namako_ (fish-roe) grounds were essential for the mountings of swords worn on ceremonial occasions, the _ishime_ (stone-pitting) or _jimigaki_ (polished) styles being considered less aristocratic. Namako is obtained by punching the whole surface--except the portion carrying the decorative design--into a texture of microscopic dots. The first makers of namako did not aim at regularity in the distribution of these dots; they were content to produce the effect of millet-seed sifted haphazard over the surface. But from the 15th century the punching of the dots in rigidly straight lines came to be considered essential, and the difficulty involved was so great that namako-making took its place among the highest technical achievements of the sculptor. When it is remembered that the punching tool was guided solely by the hand and eye, and that three or more blows of the mallet had to be struck for every dot, some conception may be formed of the patience and accuracy needed to produce these tiny protuberances in perfectly straight lines, at exactly equal intervals and of absolutely uniform size. Namako disposed in straight parallel lines originally ranked at the head of this kind of work. But a new kind was introduced in the 16th century. It was obtained by punching the dots in intersecting lines, so arranged that the dots fell uniformly into diamond-shaped groups of five each. This is called _go-no-me-namako_, because of its resemblance to the disposition of chequers in the Japanese game of _go_. A century later, the _daimyo namako_ was invented, in which lines of dots alternated with lines of polished ground. _Ishime_ may be briefly described as diapering. There is scarcely any limit to the ingenuity and skill of the Japanese expert in diapering a metal surface. It is not possible to enumerate here even the principal styles of ishime, but mention may be made of the _zara-maki_ (broad-cast), in which the surface is finely but irregularly pitted after the manner of the face of a stone; the _nashi-ji_ (pear-ground), in which we have a surface like the rind of a pear; the _hari-ishime_ (needle ishime), where the indentations are so minute that they seem to have been made with the point of a needle; the _gama-ishime_, which is intended to imitate the skin of a toad; the _tsuya-ishime_, produced with a chisel sharpened so that its traces have a lustrous appearance; the _ore-kuchi_ (broken-tool), a peculiar kind obtained with a jagged tool; and the _gozamé_, which resembles the plaited surface of a fine straw mat. Patina.