We often say that when a divine weapon is powerful, it will use iron cutting like mud to describe the sharpness of the sword, which has also become our standard evaluation of powerful cold weapons, if even iron can not be cut, it is an unreliable thing.
However, did there really exist in ancient times when the sword was as sharp as mud? The answer is no.
According to the research and identification of experts, there was indeed a sword in ancient times, but it was far from being able to cut iron like mud, the so-called cutting iron like mud is just nonsense, the ancients did not cut iron at all, but the copper coins commonly used by the ancients.
In ancient times, the iron used to build the sword was very hard, and the copper used in the copper coin was very hard, and the ancients could not clearly distinguish the obvious difference in the hardness of copper and iron, so they thought that the sword that could cut off the copper coin must be a good product!
So there is a situation that we often see in film and television dramas, some heroes or sword merchants put a stack of copper coins on the table, and then pick up the sword and cut it directly, which is the so-called cutting iron like mud.
We now know that iron is actually much harder than copper, and most of the copper coins are made of pure copper, so that the hardness of copper coins is lower, so as long as the method is appropriate, the iron sword is easy to cut off a stack of copper coins, and then ordinary people do not know what the situation is, they think that this sword is a divine weapon, so there is a saying that the iron is like mud.
The real method used to judge the quality of the sword, in fact, most of the time is to rely on the touch to see, the real cutting identification of the situation is very small, after all, the durability of the sword is like that, and then the sharp weapon will become blunt, so for the ancients, it is necessary to judge from a simpler and easier to understand aspect.
Among them, the most common is to see whether the molten iron is mature during smelting, which is recorded in the "Record of Examination Workers":
In the form of cast gold, gold and tin, the black and turbid qi are exhausted, followed by yellow and white; the yellow and white qi is exhausted, and the green and white qi is second; the green and white qi is exhausted, and the green qi is second.
This is also the origin of the later fire.
For people who buy swords, it is necessary to see whether the lines of the sword body are neat, whether the metal is rusty, whether the overall style is suitable, whether the connection between the handle and the sword body is strong, and some to see the decoration of the sword, the general decoration is too complex The sword is a sword, most of which is ornamental.
Therefore, the use of iron as mud to comment on the quality of a sword is not valid at all, a good knife or to carefully distinguish it, of course, for the ancients, fast knives and fast swords, as long as they can protect themselves, it is a good weapon.