In 1874 Remington & Sons manufactured the first commercial typewriter, called the Remington Number 1. This typewriter was designed by Christopher Sholes and used the "QWERTY" keyboard we are all familiar with.
This early typewriter used a mechanism with characters on the end of a bar. When a key was struck, a linkage would swing the bar into a tape coated with ink. When the character struck the tape, the impression of the character was transferred onto the paper, which was positioned behind the tape.

Sholes' original prototypes had a problem with the bars colliding with each other and jamming. So the story goes that he arranged the keys with the most common letters in hard to reach spots, to slow typists down and try to avoid this problem.

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