Jun yao (chinesisch 钧窑, Pinyin Jun yao, W.-G. Chün yao, englisch Jun Kiln ‚Jun-Brennofen‘) ist die Fachbezeichnung für in der Stadt Yuzhou der chinesischen Provinz Henan befindliche song-zeitliche Porzellanbrennöfen. Der Jun-Brennofen zählt zu den Fünf berühmte Brennöfen der Song-Dynastie, er wird auch Jun yao 均窑 oder Junzhou yao 钧州窑 genannt.^[1] Die Stätte wurde 1951 entdeckt. Das Jun-Porzellan hat einen dunklen Grundton mit einer blauschwarz gesprenkelten Glasur, die meist mit einem feinen Netz von Rissen überzogen ist.

钧窑也称均窑，均州窑是宋代初年，在今河南省禹州市神垕镇钧台建立的瓷窑。钧窑古瓷窑址现在是全国重点文物保护单位，原址处建有“禹州钧官窑址博物馆”^[1]。 

钧窑是中国宋代五大名窑之一，创烧于唐，兴盛于宋，复烧于金元，延至明清仍继续仿制，历经千年而不衰，形成了一个庞大的钧窑系，与汝、官、哥、定诸窑齐名。迄今为止，在禹州境内已发现北宋钧窑遗址多达四十处，尤以神垕镇大刘山下最为集中。

禹州现存最早的《钧州志》中说：“瓷窑在州西大刘山下”。在禹州市神垕镇下白峪村和苌庄乡等地，先后出土黑、褐釉高温窑变花瓷，被陶瓷学家称为“唐钧”，它是宋代钧瓷的先声。宋“靖康之变”（1126年）后，宋室南迁，官钧窑停烧，钧瓷一时受挫。到金、元时代，钧瓷有了新的发展，各地争相仿制，风靡一时，钧窑播火全国。元末明初，因战乱和灾荒，钧窑生产渐衰。明、清时期，制瓷中心南移，北方诸名窑衰退，钧窑也基本停烧。清朝晚期，钧瓷复苏。到光绪三十年（1904年），神垕镇烧制钧瓷者已有十余家。民国年间，因战乱、灾荒频繁，钧瓷生产举步维艰。至民国三十一年（1942年）后，因大旱和政局混乱，艺人外流，钧瓷生产趋于停产状态。1949年以后，特别是中国改革开放以来得到了快速发展，被做为国礼，达到了一个新的高度。

钧窑土脉细，釉彩有兔丝纹：红的像胭脂、朱沙，青翠的像葱，紫色如紫玫瑰等多种颜色，俗称海棠红、梅子青、茄皮紫、天兰等色彩。钧窑瓷器常发生窑变，除本色釉外还会变出其他颜色，而钧瓷的名贵正在于其独特的窑变釉色，其釉色是烧制过程中自然形成，非人工描绘，每一件钧瓷的釉色都是唯一的，故有“钧瓷无双”的说法，钧瓷的釉质深厚透活，晶莹玉润，有明快的流动感。

明代文震亨在《长物志》一书中对钧窑的评论：“均州窑色如胭脂者为上，青若葱翠、紫若黑色者次之，杂色者不贵。”^[2] 景德镇窑在清代也烧制仿钧窑瓷器。^[3]

Jun ware (Chinese: 鈞窯; pinyin: Jūn yáo; Wade–Giles: Chün-yao) is a type of Chinese pottery, one of the Five Great Kilns of Song dynasty ceramics. Despite its fame, much about Jun ware remains unclear, and the subject of arguments among experts. Several different types of pottery are covered by the term, produced over several centuries and in several places, during the Northern Song dynasty (960–1126), Jin dynasty (1115–1234) and Yuan dynasty (1271–1368), and (as has become clearer in recent years) lasting into the early Ming dynasty.^[1]

Some of the wares were popular, especially the drinking vessels, but others seem to have been made for the imperial court and are known as "official Jun wares"; they are not mentioned in contemporary documents and their dating remains somewhat controversial. These are mostly bowls for growing bulbs or flower-pots with matching stands, such as can be seen in many paintings of scenes in imperial palaces.^[2] The consensus that seems to be emerging, driven largely by the interpretation of excavations at kiln sites, divides Jun wares into two groups: a large group of relatively popular wares made in simple shapes from the Northern Song to (at lower quality) the Yuan, and a much rarer group of official Jun wares made at a single site (Juntai) for the imperial palaces in the Yuan and early Ming periods.^[3] Both types rely largely for their effect on their use of the blue and purple glaze colours; the latter group are sturdy shapes for relatively low-status uses such as flowerpots and perhaps spitoons.^[4]

The most striking and distinctive Jun wares use blue to purple glaze colours, sometimes suffused with white, made with straw ash in the glaze.^[5] They often show "splashes" of purple on blue, sometimes appearing as though random, though they are usually planned. A different group are "streaked" purple on blue,^[6] the Chinese describing the streaks as "worm-tracks". This is a high-prestige stoneware which was greatly admired and often imitated in later periods. But colours range from a light greenish-brown through green to blue and purple. The shapes are mostly simple, except for the official wares, and other decoration is normally limited to the glaze effects.^[7] Most often, the "unofficial" wares are wheel-thrown, but the official ones moulded.

The wares are stoneware in terms of Western classification, and "high-fired" or porcelain in Chinese terms (where the class of stoneware is not generally recognised). Like the still more prestigious Ru ware, they are often not quite fired as high as the normal stoneware temperature range, and the body remains permeable to water.^[8] They form a "close relative" of the wider group of Northern celadons or greenwares.^[9]