Many pencils across the world, and almost all in Europe, are graded on the European system using a continuum from H (commonly interpreted as “hardness”) to B (commonly “blackness”), as well as F (usually taken to mean “fineness”, although F pencils are no more fine or more easily sharpened than any other grade. also known as “firm” in Japan[45]). The standard writing pencil is graded HB.[46]
According to Petroski, this system might have been developed in the early 20th century by Brookman, an English pencil maker. It used B for black and H for hard; a pencil’s grade was described by a sequence or successive Hs or Bs such as BB and BBB for successively softer leads, and HH and HHH for successively harder ones.[47]
The Koh-i-Noor Hardtmuth pencil manufacturers claim to have originated the HB standard of gradations, with H standing for Hardtmuth, B for the company’s location of Budějovice, and F for Franz Hardtmuth, who was responsible for technological improvements in pencil manufacture.[48][49]