The OADG 109A and older 109 keyboard layouts which are the standard for Microsoft Windows have five dedicated language input keys:1
Apple keyboards designed for Mac OS X have two language input keys: alphanumeric (英数) and kana (かな).
The keyboards for NEC PC-9800 series, which was dominant in Japan during the 1980s and early 1990s, have three language input keys: kana (カナ), NFER (no transfer, same as non-conversion), XFER (transfer, same as conversion).2
For non-Japanese keyboards, the following shortcuts can be used for typing Japanese on English keyboard with Windows:
"Hankaku/Zenkaku" redirects here. For the typographical concept, see halfwidth and fullwidth forms.
Half-width/Full-width (半角/全角, hankaku / zenkaku) toggles between entering half-width or full-width characters (if 2 versions of same character exists) when IME is on and in Katakana mode or Alphanumeric mode. After MS-IME 98, and also change between IME on and off like Kanji Key.
半角/全角
漢字
Used to switch between entering mainly Japanese (IME on) and English text (IME off). It is not found as a separate key in the modern Japanese 106/109-key keyboard layout. On the Common Building Block (CBB) Keyboard for Notebooks, as many 106/109-key keyboards, the Kanji key is located on the Alt+半角/全角. It is found as a separate key on the IBM PS/55 5576-001 keyboard. On the IBM PS/55 5576-002 keyboard, it is mapped to the left Alt key.
Alphanumeric (英数, eisū) toggles alphanumeric characters. In the Japanese 106/109-key layout, it is located on the Caps Lock key. Pressing Alphanumeric/Caps Lock key alone actually means alphanumeric function, a user has to press ⇧ Shift+英数 / Caps Lock key to get the caps lock function.
Conversion (変換, henkan) is used to convert kana to kanji. In the Microsoft IME, Conversion selects conversion candidates on highlighted input, and ⇧ Shift+変換 is used to display the previous candidate, or zenkōho (前候補). The alt version of this key is also pronounced zenkōho (全候補), which means "all candidates", shows all input candidates.
前候補変換 (次候補)
全候補
Non-conversion (無変換, muhenkan) specifies that the kana characters entered are not to be converted into kanji candidates.
Katakana,hiragana,rōmaji (ひらがな / カタカナ / ローマ字, katakana,hiragana,rōmaji) used to switch between hiragana or katakana characters. It can also be found for switching between hiragana, katakana and rōmaji as shown below. Alt+ひらがな / カタカナ / ローマ字 or Ctrl+⇧ Shift+ひらがな / カタカナ / ローマ字3 (this feature is printed as Rōmaji (ローマ字) on the same key) toggles between rōmaji input and direct kana input in some IMEs (e.g. Microsoft IME).
カタカナひらがな
ローマ字
The standard keyboard layout for IBM PC compatibles of South Korea is almost identical to the U.S. layout, with some exceptions:
It toggles between entering Korean (Hangul) and English (ISO basic Latin alphabet).
Many computer systems support alternative keys or key sequences for keyboards without the Han/Yeong key. It is absent from the keyboards of most portable computers in South Korea, where the right Alt key is used instead. On the right Alt key of these devices, only "한/영" (Han/Yeong) or both "한/영" (Han/Yeong) and Alt are printed.
It converts Hangul to Chinese characters (hanja) or some special characters.
Many computer systems support alternative keys or key sequences for keyboards without the Hanja key. It is absent from the keyboards of most portable computers in South Korea, where the right Ctrl key is used instead. On the right Ctrl key of these devices, only "한자" (Hanja) or both "한자" (Hanja) and Ctrl are printed.
"OADG 109Aキーボード JISによる参照キーボードに!". Archived from the original on 23 February 2016. Retrieved 24 July 2012. https://web.archive.org/web/20160223074913/http://oadg.or.jp/archives/OADG-WEB/OADG/109A-JIS.html ↩
"Keyboard Collection". Retrieved 26 August 2017. http://www.pfu.fujitsu.com/hhkeyboard/kb_collection#nec ↩
"Caps Lock, Num Lock, and Scroll Lock Indicators Are Reversed". Microsoft Support. Retrieved 29 January 2015. http://support.microsoft.com/kb/826127/en-us ↩