The word "well matched" can be said to be well known. In short, it means equal access and equal conditions. It was first derived from the first part of the second book of Romance of the Western Chamber by the famous playwright Wang Shifu of the Yuan Dynasty: "Although not well matched, it is better to be caught in a thief". However, some people also believe that "door dang" and "door to door" refer to the two objects that decorate the door. Today, let's take a look at what they are and why they were once so important. The use of Baogu stone in civilian architecture was generally only introduced in the mid to late Qing Dynasty. It should be noted that there is no "doorman" or "household pair" in the architecture profession. Today, we use these two terms, only following the customary way of saying. First of all, let's talk about "doorstep". You may have heard a nursery rhyme, "Little Fat Man sits on the doorstep, crying for his wife." This doorstep refers to doorstep, which is the stones on the left and right sides of the door, used as pillows for the door frame and two door panels, to fix and decorate them. There are generally two types of door dang shapes: one is a round drum shape, and the commonly heard drum holding stone is one type of door dang; The other type is a square. There are also many decorative patterns on these doors, mostly using reliefs, such as "Five Blessings Holding Longevity", "Lion Embroidery Ball", "Deer and Crane in Spring", "Three Friends", and "Lin Tuyu Book", all of which are auspicious patterns. Why is there a difference between a circle and a square? At the beginning, the drum shaped "door dang" was used for military officials' residences, while the square shaped "door dang" was used for civilian officials' residences. The round drum symbolizes the wheel of the owner's battle, rolling forward unstoppably; The square is like a seal, or like the bookcase carried by scholars during their exams, square and upright. In addition, the door in the form of a drum shaped stone should be a symbol of a family's achievements and fame, which was initially only installed by official families. We now see civilian buildings under some old buildings that also have drum stones, which generally only appeared in the middle and late Qing Dynasty. This is because after the mid Qing Dynasty, buying and selling officials became rampant, and wealthy merchants also gained political capital through money, so there were more and more holding drums and stones. After the demise of the Qing Dynasty, the restrictions on the hierarchy of residences disappeared. Many bureaucrats, warlords, and rich people who moved to Beijing were no longer bound by the Ancien Régime when building or rebuilding their residences, so a large number of Baogu Stone Gate Piers remained. To add, the overall shape of the Baogu stone is round and represents the roundness of the sky and the place. In addition, official families have deep houses and large courtyards, and a drum is placed at the entrance, similar to the drum at the entrance of the yamen, which is also a symbol of official status. In short, this "drum" symbolizing merit and power was well chosen and inspiring. Having finished talking about door decorations, let's now take a look at what "door decorations" refer to. Door decorations refer to wooden or brick carvings with cylindrical or hexagonal shapes on or on both sides of traditional residential lintels, which are actually door hairpins. The door hairpin has functionality and can be used to reinforce couplets and middle sills, also known as the lintel, but its greater role is decoration. The auspicious patterns carved on the hairpin head or auspicious characters such as "wealth, nobility, safety," and "auspiciousness, luck, and happiness" are simply a physical version of the happy eyebrows. Once a door hairpin becomes a fixed decoration, it will inevitably lead to class differences. However, compared to this drum shaped stone and door hairpin, it is more important to use it to represent a "family in charge" object