> Between 1822 and 1874, more than 160 patents were registered pertaining to a variety of improvements to mechanical pencils. The first spring-loaded mechanical pencil was patented in 1877 and a twist-feed mechanism was developed in 1895. The 0.9 mm lead was introduced in 1938,[citation needed] and later it was followed by 0.3, 0.5 and 0.7 sizes. Eventually, 1.3 and 1.4 mm mechanisms were available, and 0.4 and 0.2 versions are now produced.

> The mechanical pencil became successful in Japan with some improvements in 1915 by Tokuji Hayakawa, a metal worker who had just finished his apprenticeship. It was introduced as the "Ever-Ready Sharp Pencil". Success was not immediate, since the metal shaft—essential for the pencil's long life—was unfamiliar to users. However, the Ever-Ready Sharp began selling in huge numbers after a company from Tokyo and Osaka made large orders.[9][10] Later, Tokuji Hayakawa's company got its name from that pencil: Sharp.[9]