Also known as "big red robe" or "cardinal red" (bright red and flawless), second class is "bean red", apple-red", "beauty's blush" or "drunken beauty" and come with mottles in different shades. Third category is lighter in tone and called "baby's face" or "peach blossom". Lower qualities includes "baby-mouse skin" or "elm bark", "donkey's liver" and "horse's lung" etc. Developed during the Kangxi period, recorded to have been still in use in the 1950's.
The glaze itself is a copper-based mottled glaze showing blushes of red sometimes dotted with fine green spots on a pinkish red ground where the green copper oxide have not completely been reduced to red.
While the glaze itself in particular in its bright red varities seems to have been developed in an attempt to imitate the red-glazed wares of teh Xuande perid during the Ming dynasty, the peachbloom glaze of the bean red type, was reserved almost exclusively for small porcelain objects for the scholars table, and of the "eight classic shapes" Ba da ma.
The quality of the peach bloom glaze varies a lot between individual pieces in such degree that it appears as if the variations was apperciated and judged individually depending on the beauty of each item.
The glaze appears to have been sprayed onto the pices in a manner similar to that of "powder blue", but while using copper oxide instead of cobalt, possibly sandwiched between two layers of clear glaze.
Personally I would have called this entire class "powder red" instead, to make the process understandable and make it easier to decide which monochrome red's that belongs to this group or not.