洪炉燎发
      Explanation: The furnace: a large stove. A furnace and burned hair. Metaphor to easily solve.
      Source: "Historical Legends of Assassins" husband to a feather burn charcoal in the stove top, will carry on without incident. "
      Examples: General Huang Wei this battle, soldiers have to palm, Long Xiang tiger step, compete with heart; if Yuzhu eunuchs, like a drum ~ ear. (Ming Luo, "Three Kingdoms" the second time)