When you type the alphabet on a normal keyboard with ten fingers in standard position, what is the largest number of consecutive letters of the alphabet that can be typed with the same hand?

On a standard QWERTY keyboard, the practice of touch typing assigns specific keys to each hand, with the goal of efficiency and speed. Your left-hand fingers rest on A, S, D, and F, while your right-hand fingers are positioned on J, K, L, and the semicolon. From this "home row" position, each hand is responsible for a specific set of letters. This division of labor is why you can't simply type the alphabet by alternating hands. As you type through the letters in order, you'll find that the first seven, A through G, are all typed by the left hand.

The pattern breaks with the letter H, which is the first in a long series of consecutive letters assigned to the right hand. Following H, the next eight letters in the alphabet—I, J, K, L, M, N, O, and P—are all typed using the right hand. This creates an uninterrupted sequence of nine letters. The streak is broken by Q, which brings the typing action back to the left hand. This quirk is a direct result of the QWERTY layout, which was designed by Christopher Latham Sholes in the 1870s.

The QWERTY layout was not created for alphabetical convenience, but rather to solve a mechanical problem in early typewriters: keys jamming when frequently used letters were typed in quick succession. The arrangement separates common letter pairings to prevent these jams. While modern computers don't have mechanical arms that can get stuck, the layout has persisted as the standard. This historical design is what leads to interesting typing anomalies, such as the right hand handling a nine-letter alphabetical run.