Used on typewriters before personal computers. In Unix-like operating systems this layout is standard (Keyboard GOST 6431-90). It is available in Microsoft Windows as a legacy layout.
JIUKEN, the predecessor
The JIUKEN layout was used before the Russian spelling reform of 1917. It includes the Cyrillic dotted or "decimal" I as well as Ѣ, which were eliminated after the reform, but it does not include the letters Ѳ and Ѵ, which were rare even before the reform. The numbers 1, 3 and 0 do not appear on the layout, and this forced the typist to replace them with the letters decimal I, Ze, and O respectively. The letters Ц and Э are located side-by-side; the Ѣ was between the letters Ч (Che) and С (Es). The letter Ё (yo) was not included in this layout.
After the reform, the JIUKEN layout sees the following modifications[2]:
the letter Ѣ (yat) is replaced by the letter Ё (yo).
JCUKEN, from typewriter to computer
It is only on July 1, 1953, that the norm GOST 6431-52 on the arrangement of letters, numbers and symbols on the keyboard began to operate.[2] Within a few years, Soviet typewriters switched to the new JCUKEN layout with the following modifications:
all numbers 1, 3, 0 are present in the first line;
the letter Ц is moved to the previous emplacement of number 1;
letters Ъ, Э, Ё are moved to the end of the three lines of letters.
This version is also known today in modern computer as Russian (typewriter) (ru:Русская (машинопись)).
In OpenSolaris and other Unix-like operating systems this layout is standard (Keyboard GOST 6431-90).
At the end of the 80s, when the Soviet Union began issuing analogues of IBM PC/XT personal computers, the IT Committee of proposed its own GOST 14289-88.
[3]
But this version did not follow the locations of punctuations (and various signs), neither those of the American QWERTY version, nor those of the 6431-90 version. Instead, Microsoft and the keyboard manufacturers delivered a Russian JCUKEN-QWERTY version for MS-DOS, almost analogous to the future version delivered in 1994 with Windows.
Other operating systems such as Linux may have their own additional custom layouts for the same or other languages.
Belarusian
The short U (Ў ў) is located in place of the shcha (Щ щ). It is the only JCUKEN keyboard that lacks a key for И, as it is the only language in the Cyrillic script that does not contain the letter И itself; the decimal I (І і) replaces it. It also lacks a hard sign (Ъ ъ), usually seen just to the right of letter ha (Х х) as that position is taken by the Apostrophe.
The Russian letters which are rarely used in Tatar are typed with AltGr (right Alt). This layout is also suitable for Kalmyk and Turkmen (Cyrillic) as their alphabets are practically identical to Tatar. It is called as YÖUKEN.
Bashkir
Kazakh
Kyrgyz
An "upgraded" version based on the basic Russian one, the additional Kyrgyz letters are typed with AltGr (right Alt). Thus, AltGr + У is Ү, AltGr + О is Ө, and AltGr + Н is Ң.
Yakut (Sakha)
Tajik
This is a modified version of JCUKEN called YQUKEN, in which the Ka with descender (Қ қ) substitutes the C (Ц ц). The yeru (Ы ы) is replaced by the letter Che with descender (Ҷ ҷ). Also, the soft sign (Ь ь) is replaced by the I with macron (Ӣ ӣ). Further, the Kha with descender (Ҳ ҳ) substitutes for Shcha (Щ щ), and the U with macron (Ӯ ӯ), and the ghayn (Ғ ғ) are used. (In Unicode, Kha with descender is known as "Ha with descender".)
This layout is a modified version called the JÜUKEN, and includes the Che with vertical stroke, shha, Ka with vertical stroke, and the Je. It is the only JCUKEN without the usual Й, as the language lacks the glyph, which was replaced by Je in 1958.
The Mongolian keyboard uses a modified version of JCUKEN, called FCUZHEN (ФЦУЖЭН), where letters specific to Russian are replaced by letters that see more use in Mongolian.
Other Cyrillic layouts
Serbian
In the Serbian keyboard LjNjERTZ (ЉЊЕРТЗ), letters of the Serbian language are used instead of Russian letters. It lacks the yers and yeru (Ъ ъ, Ь ь and Ы ы), Э, and Ё. It is based on the QWERTZ keyboard layout.
Macedonian
Also utilizing a modification of the Serb-style LjNjERTZ (LjNjERTDz), a single "dead key" is used for input for Macedonian letters Gje "Ѓ ѓ" and Kje "Ќ ќ", as well as the typewritten apostrophe (in combination with the spacebar): «м. к. á», «К к» → «Ќ ќ», «м. к. á», «space» → «'».
Macedonian keyboard layouts under Microsoft Windows (KBDMAC.DLL and KBDMACST.DLL) do not use "dead keys". Instead, letters Gje and Kje are present as dedicated keys, and AltGr is used to access additional letters and punctuation.
Bulgarian
The Bulgarian language utilizes the unique layout ,УЕИШЩ (,UEIShSht) developed for typewriters in the 1900's, with the addition of two Russian letters (Э and Ы) due to vacant keys after spelling reforms. The letter Ы can be typed by Shift + , (comma). The letter Ѝ can by typed through Shift + Ь. Because of this, typing capital Ь, Ы and Ѝ is impossible without the use of the Caps Lock key.
In addition, the Bulgarian language has two additional keyboard layoutsː The Phonetic layout ЧШЕРТЪ (ChShERTǍ) and the more widely used Traditional Phonetic layout ЯВЕРТЪ (YaVERTǍ)
Standard Cyrillic keyboard layout for Bulgarian in 2006 (Also known as ",УЕИШЩ" (,UEIShSht))
Phonetic Cyrillic keyboard layout for Bulgarian in 2006 (Also known as "ЧШЕРТЪ" (ChShERTǍ))
Traditional Phonetic Cyrillic keyboard for Bulgarian in 2006 (Also known as "ЯВЕРТЪ" (YaVERTǍ))
Latin JCUKEN
This was the predominant layout on the Soviet-made microcomputers during the 1980s - the Cyrillic characters on most keys being supplemented with their Latin equivalents, and punctuation filling gaps where no direct Latin equivalent exists.
JCUKEN/QWERTY layout combo
Nowadays, however, a different approach is used in keyboards designed for Russian users. Most keyboards in Russia of XXI century have two letters per key, one for JCUKEN and one for QWERTY. This design, for example, was used for the Keyboard Monument.
One can see a design nuance, where two homoglyphs share one key: Latin C letter is located on the same key as Cyrillic С.