To solve the problem that a stone material used for a seal material for seal engraving now gets easily chipped by an impact in the case where the seal face of an engraved seal falls or in the case where the engraved seal collides with the fringe of an Indei (a vermilion inkpad) of porcelain because the stone material is low in hardness (about 3 to 10 degree) and has a large fluctuation.

The bincho charcoal made from hard Quercus phillyraeoides or Quercus glauca as raw wood is used as a seal material for seal engraving. The bincho charcoal is hard with the hardness of 20 degree and free from fluctuation. Radial line shape wood grain is used, the angle of an engraving knife relative to an engraving face is constantly held in 50 to 60°, the engraving knife is put in a direction perpendicular to the radial line shape wood grain, a thrust knife and a pull knife are used in a seal engraving method, thereby the problem overcome. As a result, an engraved elegant seal excellent in durability which does not get chipped against the impact at all can be made.

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