A third group is also consistently labelled Ming, but with better reason, though even here a little more elasticity in the dating is advisable. It has an exact parallel in porcelains of undoubted Ming origin, viz. those represented by Plate 61, etc., which usually take the form of jars and vases with designs outlined in fillets of clay, or channelled or even pierced _à jour_. The spaces between the outlines are filled with coloured glazes which are fired, in the case of porcelain, in the cooler parts of the biscuit kiln. These are the glazes _de demi-grand feu_, according to the French definition, and they consist of turquoise and aubergine purple or violet and green (the three colours or _san ts´ai_, all minutely crackled), supplemented by a white formed by slip and a thin brownish yellow. Occasionally the purple is so deep as to appear almost black; and the details of the designs are often etched in the paste with a fine point. Precisely similar wares are found with an earthenware body; and they are, no doubt, contemporary with the analogous porcelains, though how long the traditions of this type of ware continued has never been precisely determined. The porcelain on which washes of turquoise and aubergine glaze are combined is a development of this type, and this has certainly survived to comparatively modern times. Reticulated ornament was used on the three-colour pottery vases no less than on the porcelain (Plate 55); and besides the covered wine jars and vases there are figures and grotto pieces of similar style both in pottery and porcelain, many of which must date from Ming times.