Dagger combat was a skill that the Xueyu unit needed to master. Combat in the dark was a tradition in the team. It was a specialty of the team to be ruthless behind people's backs.
Some people thought that dagger combat was already outdated. Some even said that if one tried a sneak attack, others would blast one into the sky with a cannonball.
This was a classic case of talking without knowledge!
For instance, when one was rescuing the hostages, could one fire a cannonball at the other party and kill the criminals while clearing the hostages at the same time?
Hence, even if information technology became more and more widespread in the future and long-range combat would become the dominant force on the battlefield, there would always be sneak attacks. They must not fall behind!
It was the same for dagger combat.
