Uni Hexagonal Body Pencil for Kohitsu, 4B & 6B Set (Japan Import) [Komainu-Dou Original Package] Hardness of the core: 4B & 6B 4B, Pack of 3. 6B, Pack of 3. Total 6 Penciles. It is impregnated with a special oil to the core of luxury clay, less broken, achieving a smooth writing. The pencil suitable for calligraphy . They achieves an abundant expression.