Historical kana orthography
The historical kana orthography (歴史的仮名遣 rekishiteki kanazukai ), or old orthography (旧仮名遣 kyūkanazukai ), refers to the kana orthography (正仮名遣 seikanazukai) in general use until orthographic reforms after World War II; the current orthography was adopted by Cabinet order in 1946. By that point the historical orthography was no longer in accord with Japanese pronunciation. It differs from modern usage (Gendai Kanazukai) in the number of characters and the way those characters are used.
The historical orthography is found in most Japanese dictionaries, such as Kōjien. In the current edition of the Kōjien, if the historical orthography is different from the modern spelling, the old spelling is printed in tiny katakana between the modern kana and kanji transcriptions of the word. Ellipses are used to save space when the historical and modern spellings are identical. Older editions of the Kōjien gave priority to the historical orthography.
The historical orthography should not be confused with hentaigana, alternate kana that were declared obsolete with the orthographic reforms of 1900.
General differences 
- This section uses Nihon-shiki romanization for づ, ず, ぢ, じ, ゐ, and ゑ.
In historical kana usage:
- Two kana are used that are obsolete today: ゐ/ヰ wi and ゑ/ヱ we. These are today read as i and e. Words that formerly contained those characters are now written using い/イ i and え/エ e respectively.
- Outside of its use as a particle, the を wo kana is used to represent the o sound in some, but not all, words.
- Yōon sounds, such as しょう shō or きょう kyō, are not written with a small kana (ゃ, ゅ, ょ); depending on the word, they are written with either two or three full-sized kana. If written with two kana and the last one is や ya, ゆ yu, or よ yo, then it represents a short syllable of one mora, such as きよ kyo. If written with two or three kana and the last one is う u or ふ fu, then it represents a long syllable of two moras. The first kana is not always the same as one used in the modern spelling, as in 今日 kyō "today", written けふ kefu. If written with three kana, the middle one will always be や ya, ゆ yu, or よ yo, and the last kana will always be う u or ふ fu, as in 丁 chō, the counter for tools, guns, etc., written ちやう chiyau.
- The series of kana ha hi fu he ho are used to represent, in some words, the sounds wa, i, u, e, o, respectively.
- Precedence is given to grammar over pronunciation. For example, the verb warau (to laugh), is written わらふ warafu, and in accordance with Japanese grammar rules, waraō, the volitional form of warau, is written わらはう warahau.
- The kana づ du and ぢ di, which are mostly only used in rendaku in modern kana usage, are more common. Modern kana usage replaces them with the identically-pronounced ず zu and じ ji in most cases. For example, ajisai (hydrangea) is written あぢさゐ adisawi.
Most of the historical kana usage has been found to accurately represent certain aspects of the way words sounded during the Heian period. As the spoken language has continued to develop, some orthography looks odd to the modern eye. As these peculiarities follow fairly regular patterns, they are not difficult to learn. However, some of the historical kana usages are simply mistakes. For example,
- 或いは aruiwa (or) might be found written incorrectly as: 或ひは or 或ゐは
- 用ゐる mochiiru (use) might be found written incorrectly as: 用ひる
- つくえ tsukue (desk, table) might be found written incorrectly as: つくゑ
- えびす ebisu (barbarian, savage) might be found written incorrectly as: ゑびす, according to the old pronunciations.
Some forms of unusual kana usage are not, in fact, historical kana usage. For example, writing どじょう dojō (loach, a sardine-like fish) in the form どぜう dozeu is not historical kana usage (which was どぢやう dodiyau), but a kind of slang writing originating in the Edo period.
Here are some representative examples showing the historical and modern spellings and the kanji representation.
|Historical usage||Current usage||Kanji||Translation|
|ゐる||wiru||いる||iru||居る||there is/are (humans/animals)|
|あはれ||ahare||あわれ||aware||哀れ||sorrow; grief; pathos|
|かへる||kaheru||かえる||kaeru||帰る||to return home|
|とうきやう||Toukiyau||とうきょう||Tōkyō||東京||Tokyo, the city of|
The table at the bottom gives a more complete list of the changes in spelling patterns.
Current usage 
Historical kana usage can be used to look up words in larger dictionaries and dictionaries specializing in old vocabulary, which are in print in Japan. Because of the great discrepancy between the pronunciation and spelling and the widespread adoption of modern kana usage, historical kana usage is almost never seen, except in a few special cases. Companies, shrines and people occasionally use historical kana conventions such as ゑびす (Ebisu), notably in Yebisu beer, which is written ヱビス webisu but pronounced ebisu.
The use of を wo, へ he, and は ha instead of お o, え e, and わ wa for the grammatical particles o, e, wa is a remnant of historical kana usage.
Readers of English occasionally encounter words romanized according to historical kana usage, in which e was typically rendered ye, in accordance with the pronunciation of the 16th through 19th centuries. Here are some examples, with modern romanizations in parentheses:
- Inouye (Inoue): a Japanese family name
- Yen (En): the basic unit of Japanese currency
- Tokugawa Iyeyasu (Ieyasu)
- Uyeno (Ueno): a place name
- Yedo (Edo): a former name of Tokyo
- Kwannon (Kannon): A Bodhisattva
- Kwaidan (Kaidan), meaning ghost story, the title of a collection of Japanese ghost stories compiled by Lafcadio Hearn
- Kwansei Gakuin University (Kansai): A university in Kobe and Nishinomiya
- Iwo Jima (Iō-jima; now officially Iōtō): An island known as the site of a battle during World War II
- Iwanami kogo jiten ISBN 4-00-080073-6 or any other classical Japanese dictionary