So, in English, H stands for “Hardness” and B stands for Blackness, but… these aren’t opposites. This suggests that English isn’t the original source of this system, and the English words were created to fit the system. I was interested to find out the original origin of this scale, but it’s a little contested, different sources claim different reasons for the use of these letters.

There are some difficulties – firstly, the scale isn’t standardized, which means there’s no official authority. This also causes a separate problem as each company has a different idea of what an HB pencil is: so if you swap brands you might get a different hardness.

Secondly, Japanese companies sometimes uses F for a pencil between HB and H, in English this is supposed to mean “firm”… but it’s an odd outlier in the middle of the scale.

Thirdly, there seem to be a lot of spurious claims about the source of this system, plenty of sites say “it’s based on the English words “Hardness” and “Blackness””… but if you were an english speaker and you were creating this scale, you’d go with “hardness” and “softness” or “dark” and “light” or “black” and “pale” or the like…

America, as it always does, seems to use a completely different system of numbers that runs from 1 (for a B pencil) to 4 (for a 2H pencil) and basically doesn’t cover very hard or soft pencils. While I’ve never seen pencils with this scale marked on them I have heard “number 2 pencil” in American media (an HB pencil) – but that’s unhelpful for searching for an origin of this scale.

The HB scale for pencil grading has been around for over 200 years, and in my searches I’ve found two credible origins:

The first one is that the scale was originally coined “somewhere in France” – and the first recorded uses of this lettering coincide with a period where France was standardizing a lot of other weights and measures such as the Kilogram. In French, H stands for “Haut” and B stands for “Bas” – the pencils being called “high” and “low, referring to the amount of binder used in the lead (higher amounts lead to a harder lead.)

Secondly, the Czech company Koh-I-Noor claim to have invented the HB scale in the late 1700s. Koh-I-Noor were responsible for quite a lot of advancements in pencil technology at the time. Koh-I-Noor say that H stands for “Hardmuth” the surname of their founder, and B stands for Budějovice, the city that the company was based in, they also claim that F stands for “Franz Hardmuth” who was responsible for quite a lot of advancements in pencil technology. This is a very plausible source for an absolutely terrible naming system, so it stands to reason that this is the one that’s on Wikipedia.