KOI8-U

Short description: Character encoding for Ukrainian Cyrillic

KOI8-U

Language(s)	Ukrainian, Russian, Bulgarian
Classification	8-bit KOI, extended ASCII
Extends	KOI8-B
Based on	KOI8-R
Other related encoding(s)	KOI8-RU, KOI8-F

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, "Русский Текст" in KOI8-U becomes rUSSKIJ tEKST ("Russian Text") 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

SP

!

"

#

$

%

&

'

(

)

*

+

,

-

.

/

0

1

2

3

4

5

6

7

8

9

:

;

<

=

>

?

@

A

B

C

D

E

F

G

H

I

J

K

L

M

N

O

P

Q

R

S

T

U

V

W

X

Y

Z

[

\

]

^

`

a

b

c

d

e

f

g

h

i

j

k

l

m

n

o

p

q

r

s

t

u

v

w

x

y

z

{

|

}

~

─ 2500

│ 2502

┌ 250C

┐ 2510

└ 2514

┘ 2518

├ 251C

┤ 2524

┬ 252C

┴ 2534

┼ 253C

▀ 2580

▄ 2584

█ 2588

▌ 258C

▐ 2590

░ 2591

▒ 2592

▓ 2593

⌠ 2320

■ 25A0

∙ 2219

√ 221A

≈ 2248

≤ 2264

≥ 2265

NBSP

⌡ 2321

° 00B0

² 00B2

· 00B7

÷ 00F7

═ 2550

║ 2551

╒ 2552

ё 0451

є 0454

╔ 2554

і 0456

ї 0457

╗ 2557

╘ 2558

╙ 2559

╚ 255A

╛ 255B

ґ 0491

╝ 255D

╞ 255E

╟ 255F

╠ 2560

╡ 2561

Ё 0401

Є 0404

╣ 2563

І 0406

Ї 0407

╦ 2566

╧ 2567

╨ 2568

╩ 2569

╪ 256A

Ґ 0490

╬ 256C

© 00A9

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

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

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

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

  Differences with KOI8-R (non-Russian letters)

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).

See also

• KOI character encodings
• Ukrainian alphabet

Further reading

• "Locale::RecodeData::KOI8_U - Conversion routines for KOI8-U". CPAN libintl-perl. 2016. http://search.cpan.org/~guido/libintl-perl/lib/Locale/RecodeData/KOI8_U.pm. 
• RFC 2319
• "KOI8-U (RFC 2319)". Kermit. Columbia University. http://www.columbia.edu/kermit/ftp/charsets/koi8u.txt. 
• "KOI8-U Belorussian/Ukrainian Cyrillic to Unicode 2.1 mapping table - Based on RFC 2319". Department of Mathematical Sciences, New Mexico State University. 2008. https://www.math.nmsu.edu/~mleisher/Software/csets/KOI8U.TXT. 
• "CYRILLIC ENCODING FAQ Version 1.3". 1993-03-13. http://www.columbia.edu/kermit/ftp/charsets/cyrillic-summary.txt. 

External links

• "The Cyrillic Charset Soup". 1998-11-30. http://czyborra.com/charsets/cyrillic.html. 
• "Cyrillic Information Representation in Electronic Form - Character Set (Code Page) Tables". http://www.iis.ru/cyrillic/resource/tables.en.html. 
• "Review of 8-bit Cyrillic encodings universe". 2013. http://segfault.kiev.ua/cyrillic-encodings/. 
• https://web.archive.org/web/20050206230944/http://www.net.ua/KOI8-U/