Then, in the center of the isolation area, he lit a bonfire, continually adding dry bamboo joints and hardwood.
He didn't want dancing flames but rather the red-hot charcoal left after the fire extinguished.
"Direct scorching with fire is unstable; the heat will scatter," he explained to the camera, "In the wilderness, the most efficient and controllable heat source for precision cutting is always charcoal."
After more than ten minutes, the fire had accumulated enough high-quality charcoal.
Using long chopsticks made from two wet branches, he picked up a piece of red-hot charcoal and walked toward the bamboo that had been marked with lines.
He pressed the scorching charcoal precisely onto the circular groove.
"Sizzle——!"
A piercing sound, like a branding iron searing wet wood, suddenly exploded!
The moisture inside the bamboo vaporized instantly under the high temperature, white steam spraying out through the groove's gaps, accompanied by a strong burnt odor.
