(一) 1, the nature of the kiln is the same。All of them were kilns for the imperial court, burning both ritual and furnishings, as well as daily necessities;2. The enamel and shape are the same。All of them are kilns for celadon firing, the glaze is milky and half opaque。Ru kiln is mainly blue，There are also pink blue, sky blue shades，The main products of Tiger Cave kiln are pink blue and beige.Most of the objects have splinters，Both ice crack or fish scale;The utensils with the same shape of the two kilns mainly include washing, plates, bowls, gooseneck bottles, plum bottles, paper mallet bottles, sets of boxes, cup holders, lid and so on，Many objects are moulded，No different;3, kiln and firing process is the same。The most common is a round pancake-shaped branch with 5 nails, there are also many round cushion cakes and washers, some large utensils may use the method of naked burning;The two kilns are burned twice, and many utensils are burned on foot.

Southern Song Dynasty Guan kiln paper let down bottle

(二) The difference between the two kilns：

1、Kiln structure is different。Ru kiln is a common semi-inverted flame steamed bun kiln in northern China, the kiln is small, the kiln temperature is high, and it is easy to control the fire, so the celadon glaze is pure;The Tiger Cave kiln is a common long slope type dragon kiln in southern China. The temperature of the kiln chamber is slow and the cooling is fast. The atmosphere of the kiln chamber is difficult to control, so the celadon glaze is gray and not as bright as your porcelain.
   2, each product has its own characteristics。

(1) There are differences in fetal glaze: Tiger Cave kiln uses local purple gold soil and clay as raw materials, which contains a large amount of iron oxide components, so the fetal color is darker, and the fetal body is black, purple or grayish brown, while the Ru kiln is fragrant gray;The glaze color of Tiger Cave kiln is darker blue, while the glaze color of Ru kiln is lighter, and there is no beige ware.

(2) There are differences in the types of vessels: the Gu, Ding type furnace, Li type furnace, sandwich bowl, wearing bottle, hole set bottle, slag bucket pot, etc., are not seen in the Ru kiln, and the lotus bowl, double fish pattern wash, lotus stove, hexagonal obo box, etc., are also not seen in the Tiger Cave kiln;

(3) The decoration is different: the Tiger Cave kiln is not heavily decorated，Only a small number of bowls and plates are engraved with lotus petals，Flowerpot under the lip decorate a week with additional heaps of lace，The abdomen of the bottle is decorated with two groups of tangled branches and flowers，And Ru kiln decoration variety，Lotus pattern is the most common，There are also dragon pattern, fish pattern and the decoration of the first ring，There are also sculptures of birds and dragons，Realistic image，elaborate;

(4) There are differences in the firing process: Ru kiln uses two kinds of nail burning and pad cake burning，The nail marks are 3 or 5 small sesame seeds，The cross section of the support nails is white，And the tiger cave kiln in addition to branch burning and pad cake pad burning，The burn marks are round and large，The cross section of the support nails is black，The number of pins is mostly 5 or 6，There are also seven or eight，Up to 13 pieces，And a lot of big stuff，Such as bottle, basin, wash, bowl type outer bottom scraping glaze，Use ring gasket to burn;3, defective products are treated differently。Ru kiln is to break the defective products and throw them away on the spot, and the porcelain pieces are small;The Tiger cave kiln is not disposed at will, but after breaking the defective products, it is consciously buried deep in the special porcelain chip pit covered with pure loess to avoid outward loss, and the porcelain chips in the pit can basically be restored to complete objects。

Southern Song tiger hole Guan kiln paper let down bottle