The “triple-set” typewriter developed by Kong Byung-woo (1906-1995), a Korean ophthalmologist and a Hangeul (Korean alphabet) researcher, is one of Korea’s first Hangul typewriters mass-produced by US-based Underwood Typewriter Company during the mid-20th century. Unlike the Hangeul typewriter used by Koreans today, which features a “double-set” keyboard layout, Gong’s typewriter exhibits a “triple-set” layout containing the end consonants in addition to the first consonants and vowels. The development of the “triple-set” typewriter is based on linguistic principles that led to the invention of the Korean writing system. As one of the first Hangeul typewriters mass-produced to be used for practical purposes, this keyboard machine played an important role in the development of mechanical writing in Korean alphabet.”