Having figured this out, Han Fei didn't hit the seal again because no matter how many times it was smashed, it might not work.
"A good formation is invisible and formed naturally by the heavens and the earth. However, since the formation is formed naturally, there must be a way to break it."
This was the first sentence in the "Spirit Gathering Scripture" left by Old Jiang, which meant that a good formation was not necessarily made but naturally formed by the heavens and the earth. Only this way could the formation be invisible.
However, it also explained that any formation had a way to be broken.
Han Fei had studied formations for a year. Although his knowledge about formations was not profound enough, he knew the basics.
