Using wood as fuel, they found that charcoal made by burning wood gave off less smoke and generated higher heat.

To make charcoal for metal smelting, oak and pine trees were used.

When ironing clothes and heating rooms, charcoals from paulownia and ash trees were chosen.

Charcoal from willow and camellia trees were suitable for polish.

Charcoal was also applied to preparing food. In particular, some pieces of charcoal were put in jars for making soybean sauce and kimchi.