As we all know, tomb robbers have existed since ancient times, in the Warring States Period, there was a matter of digging tombs to fill the military salary, and it was particularly widespread at the end of the Eastern Han Dynasty. 
Cao Cao's largest tomb is the tomb of King Han of Mangdang Mountain, which is the tomb of King Xiao of Liang, and it is said that the gold and silver treasures dug up are enough for his army for three years, which shows that the income of tomb robbery is huge, and many people are involved in tomb robbery under such huge interests. However, although there are many tomb robbers, there are very few people who really know how to rob tombs, for example, finding ancient tombs is a very difficult thing, people who have this ability are the leaders of tomb robbers, tomb robbing is also a technical job, and it is a high-means technical work. In the eyes of outsiders, tomb robbers are a mysterious thing, ordinary people can't do it, in fact, it's not so, as the saying goes: "A piece of paper in the rivers and lakes, it's worthless to break a penny", tomb robbing is also a trick, as long as you master these two means, everyone can become a captain who touches gold. The first trick is to "look at the color of the grass", from the literal meaning, it is to check the color of the grass and trees, where there are ancient tombs, the surface vegetation is different from the places without ancient tombs, and the tomb robbers in film and television dramas take a compass to turn around, most of them fool people. By looking at the grass color of the vegetation is more intuitive, the sand used in the tomb sealing in the place where there is a tomb is treated, and it is difficult to grow weeds on these sandy soils, even if hundreds of years have passed, weeds can not retain rainwater, resulting in grass and trees are easy to wither yellow. 
In this way, even in the season of lush vegetation, there must be less grass and trees in the place where there are tombs, or enter the yellowing period in advance, and there are ancient tombs under the ten ** in such a place, which is a lot of examples, and the famous Qin Gong No. 1 Tomb was found in this way. Qin Gong No. 1 tomb is the largest ancient tomb excavated in China so far, was discovered by archaeologists in 1975, before the Qin Gong No. 1 tomb was excavated, there was originally a crop field on the acre, but the incompetence of the good and bad, the ground dealers did not have much harvest. So it was abandoned by the villagers, I didn't expect that even the weeds could not grow much, and then an archaeologist happened to hear the villagers mention this strange thing, judging that there may be ancient tombs underground, and excavated after reporting, and sure enough, it was a huge ancient tomb underneath. "Look at the grass color" is a more intuitive way to find the ancient tomb, the second way is to look at the "mud marks", the author said above, the ancient tomb in the backfill, in order to avoid the tomb damp and water, the sealed soil is usually burned or fried in the pot. 
This kind of soil is constantly absorbing water, and it is easy to dry when the sun is basked, and it is based on this that after the rainy day, you can check the humidity of the soil to find the ancient tomb, and the place where it is dried first is very likely to have the location of the ancient tomb.