At 3.5 inches, the blades and the knife itself, which measures just over 4 inches closed, is the perfect size; it’s not so small that it feels like a pen knife when you’re trying to do something ...

Shortly thereafter, he was joined by pen-knife maker Philip Unwin, and, by the late 1820s, the new firm of Unwin & Rodgers was advertising a line of small knives and assorted sundries ...

A small knife was used for this. It marks the origin of the pen knife. Before 1850, the process for vulcanization of rubber had not been discovered, and the only way to correct a writing mistake ...