# KOI8-U

KOI8-U (RFC 2319) is an 8-bit character encoding, designed to cover Ukrainian, which uses a Cyrillic alphabet. It is based on KOI8-R, which covers Russian and Bulgarian, but replaces eight box drawing characters with four Ukrainian letters Ґ, Є, І, and Ї in both upper case and lower case.
KOI8-RU is closely related, but adds Ў for Belarusian. In both, the letter allocations match those in KOI8-E, except for Ґ which is added to KOI8-F.
In Microsoft Windows, KOI8-U is assigned the code page number 21866. In IBM, KOI8-U is assigned code page/CCSID 1168.
KOI8 remains much more commonly used than ISO 8859-5, which never really caught on. Another common Cyrillic character encoding is Windows-1251. In the future, both may eventually give way to Unicode.
KOI8 stands for Kod Obmena Informatsiey, 8 bit (Russian: Код Обмена Информацией, 8 бит) which means "Code for Information Exchange, 8 bit".
The KOI8 character sets have the property that the Russian Cyrillic letters are in pseudo-Roman order rather than the natural Cyrillic alphabetical order as in ISO 8859-5. Although this may seem unnatural, it has the useful property that if the eighth bit is stripped, the text can still be read (or at least deciphered) in case-reversed transliteration on an ordinary ASCII terminal. For instance, "Код Обмена Информацией" in KOI8-U becomes kOD oBMENA iNFORMACIEJ (the Russian meaning of the "KOI" acronym) if the 8th bit is stripped.

## Character set

The following table shows the KOI8-U encoding. Each character is shown with its equivalent Unicode code point.
KOI8-U :
| | 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | A | B | C | D | E | F |
| 0x | | | | | | | | | | | | | | | | |
| 1x | | | | | | | | | | | | | | | | |
| 2x | SP | ! | " | # | $ | % | & | ' | ( | ) | * | + | , | - | . | / |
| 3x | 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | : | ; | < | = | > | ? |
| 4x | @ | A | B | C | D | E | F | G | H | I | J | K | L | M | N | O |
| 5x | P | Q | R | S | T | U | V | W | X | Y | Z | [ | \ | ] | ^ | _ |
| 6x | ` | a | b | c | d | e | f | g | h | i | j | k | l | m | n | o |
| 7x | p | q | r | s | t | u | v | w | x | y | z | { | | | } | ~ | |
| 8x | ─ 2500 | │ 2502 | ┌ 250C | ┐ 2510 | └ 2514 | ┘ 2518 | ├ 251C | ┤ 2524 | ┬ 252C | ┴ 2534 | ┼ 253C | ▀ 2580 | ▄ 2584 | █ 2588 | ▌ 258C | ▐ 2590 |
| 9x | ░ 2591 | ▒ 2592 | ▓ 2593 | ⌠ 2320 | ■ 25A0 | ∙ 2219 | √ 221A | ≈ 2248 | ≤ 2264 | ≥ 2265 | NBSP | ⌡ 2321 | ° 00B0 | ² 00B2 | · 00B7 | ÷ 00F7 |
| Ax | ═ 2550 | ║ 2551 | ╒ 2552 | ё 0451 | є 0454 | ╔ 2554 | і 0456 | ї 0457 | ╗ 2557 | ╘ 2558 | ╙ 2559 | ╚ 255A | ╛ 255B | ґ 0491 | ╝ 255D | ╞ 255E |
| Bx | ╟ 255F | ╠ 2560 | ╡ 2561 | Ё 0401 | Є 0404 | ╣ 2563 | І 0406 | Ї 0407 | ╦ 2566 | ╧ 2567 | ╨ 2568 | ╩ 2569 | ╪ 256A | Ґ 0490 | ╬ 256C | © 00A9 |
| Cx | ю 044E | а 0430 | б 0431 | ц 0446 | д 0434 | е 0435 | ф 0444 | г 0433 | х 0445 | и 0438 | й 0439 | к 043A | л 043B | м 043C | н 043D | о 043E |
| Dx | п 043F | я 044F | р 0440 | с 0441 | т 0442 | у 0443 | ж 0436 | в 0432 | ь 044C | ы 044B | з 0437 | ш 0448 | э 044D | щ 0449 | ч 0447 | ъ 044A |
| Ex | Ю 042E | А 0410 | Б 0411 | Ц 0426 | Д 0414 | Е 0415 | Ф 0424 | Г 0413 | Х 0425 | И 0418 | Й 0419 | К 041A | Л 041B | М 041C | Н 041D | О 041E |
| Fx | П 041F | Я 042F | Р 0420 | С 0421 | Т 0422 | У 0423 | Ж 0416 | В 0412 | Ь 042C | Ы 042B | З 0417 | Ш 0428 | Э 042D | Щ 0429 | Ч 0427 | Ъ 042A |
Although RFC 2319 says that character 0x95 should be U+2219 (∙), it may also be U+2022 (•) to match the bullet character in Windows-1251.
Some references have a typo and incorrectly state that character 0xB4 is U+0403, rather than the correct U+0404. This typo is present in Appendix A of RFC 2319 (but the table in the main text of the RFC gives the correct mapping).