JCUKEN

JCUKEN (ЙЦУКЕН, also known as YCUKEN, YTsUKEN and JTSUKEN) is the main Cyrillic keyboard layout for the Russian language in computers and typewriters. Earlier in Russia JIUKEN (ЙІУКЕН) layout was the main layout, but it was replaced by JCUKEN when the Russian alphabet reform of 1917 removed the letters Ѣ, І, Ѵ, and Ѳ. The letter Ъ had decreased in usage significantly after the reform.

Alternative layouts include the Russian phonetic keyboard layouts, in which Cyrillic letters correspond to similar-sounding Latin letters in QWERTY and other layouts.