Dr. Torigata Uichi invented the world's first practical wireless telephone (the T.Y.K wireless telephone) in February 1912 (Meiji 45) at the age of 29. The name T.Y.K was formed from the initials of the three inventors Torigata Uichi, Yokoyama Eitaro and Kitamura Seijiro. The T.Y.K wireless telephone was a significant invention in that it provided a practical wireless telephone in the era before vacuum tubes were available. The device combined a crystal receiver with a spark-type transmitter that used a special electrode and direct current.