Adjectives in Japanese use okurigana to indicate aspect and affirmation-negation, with all adjectives using the same pattern of suffixes for each case. A simple example uses the character 高 (high) to express the four basic cases of a Japanese adjective. The root meaning of the word is expressed via the kanji (高, read taka and meaning "high" in each of these cases), but crucial information (aspect and negation) can only be understood by reading the okurigana following the kanji stem. 高い (takai) : High (positive, imperfective), meaning "[It is] expensive" or "[It is] high" 高かった (takakatta) : High (positive, perfective), meaning "[It was] expensive/high" 高くない (takakunai) : High (negative, imperfective), meaning "[It is not] expensive/high" 高くなかった (takakunakatta) : High (negative, perfective), meaning "[It was not] expensive/high"
Japanese verbs follow a similar pattern; the root meaning is generally expressed by using one or more kanji at the start of the word, with aspect, negation, grammatical politeness, and other language features expressed by following okurigana. 食べる (taberu) : Eat (positive, imperfective, direct politeness), meaning "[I/you/etc.] eat" 食べない (tabenai) : Eat (negative, imperfective, direct), meaning "[I/you/etc.] do not eat" 食べた (tabeta) : Eat (positive, perfective, direct), meaning "[I/you/etc.] ate/have eaten" 食べなかった (tabenakatta) : Eat (negative, perfective, direct), meaning "[I/you/etc.] did not eat/have not eaten"
Compare the direct polite verb forms to their distant forms, which follow a similar pattern, but whose meaning indicates more distance between the speaker and the listener: 食べます (tabemasu) : Eat (positive, imperfective, distant politeness), meaning "[My group/your group] eats" 食べません (tabemasen) : Eat (negative, imperfective, distant), meaning "[My group/your group] does not eat" 食べました (tabemashita) : Eat (positive, perfective, distant), meaning "[My group/your group] ate/has eaten" 食べませんでした (tabemasen deshita) : Eat (negative, perfective, distant), meaning "[My group/your group] did not eat/has not eaten"
The okurigana for group I verbs (五段動詞 godan dōshi) usually begin with the final syllable of the dictionary form of the verb. 飲む no-mu to drink, 頂く itada-ku to receive, 養う yashina-u to cultivate, 練る ne-ru to twist.
For group II verbs (一段動詞 ichidan dōshi) the okurigana begin at the syllable preceding the last, unless the word is only two syllables long. 妨げる samata-geru to prevent, 食べる ta-beru to eat, 占める shi-meru to comprise, 寝る ne-ru to sleep, 着る ki-ru to wear
If the verb has different variations, such as transitive and intransitive forms, then the shortest reading of the kanji is used for all related words. 閉める shi-meru to close (transitive), 閉まる shi-maru to close (intransitive), 落ちる o-chiru to fall, 落とす o-tosu to drop
Distinctions are also made to differentiate between readings. 脅かす obiya-kasu to threaten (mentally), 脅す odo-su to threaten (physically)
Most adjectives ending in -i (true adjectives) have okurigana starting from the -i. 安い yasu-i, 高い taka-i, 赤い aka-i
Okurigana starts from shi for adjectives ending in -shii. 楽しい tano-shii, 著しい ichijiru-shii, 貧しい mazu-shii
Exceptions occur when the adjective also has a verbal form. In this case, as above, the reading of the character is kept constant. 暖める atata-meru (verb), 暖かい atata-kai (adjective), 頼む tano-mu, 頼もしい tano-moshii
As with verbs, okurigana is used to distinguish between readings. 細い hoso-i, 細かい koma-kai, 大いに oo-ini, 大きい oo-kii
Na-adjectives (adjectival verbs) that end in -ka have okurigana from the ka. 静か shizu-ka, 豊か yuta-ka, 愚か oro-ka
The last syllable of an adverb is usually written as okurigana. 既に sude-ni, 必ず kanara-zu, 少し suko-shi
Nouns do not normally have okurigana. 月 tsuki, 魚 sakana, 米 kome.
However, if the noun is derived from a verb or adjective, it may take the same okurigana, although some may be omitted in certain cases. 当たり a-tari, 怒り ika-ri, 釣り tsu-ri
For some nouns it is obligatory to omit the okurigana, despite having a verbal origin. 話 hanashi, 氷 koori, 畳 tatami
The noun form of the corresponding verb does take okurigana.
話し hana-shi is the nominal form of the verb 話す hana-su, and not the noun 話 hanashi.
Some nouns have okurigana by convention. 兆し kiza-shi, 幸い saiwa-i, 勢い ikio-i
Okurigana may be omitted if there is no ambiguity in meaning or reading. 受け付け u-ke tsu-ke, 受付 uke tsuke, 行き先 i-ki saki, 行先 iki saki
There are however exceptions to these rules that must be learnt: okurigana that has become standard by convention rather than logic. 明るい aka-rui, 恥ずかしい ha-zukashii
Okurigana are also used to disambiguate kanji that have multiple readings. Since kanji, especially the most common ones, can be used for words with many (usually similar) meanings — but different pronunciations — key okurigana placed after the kanji help the reader to know which meaning and reading were intended.
Disambiguation examples include common verbs which use the characters 上 (up) and 下 (down): 上がる (agaru) : "to ascend/to make ready/to complete", in which 上 is read a 上る (noboru) : "to go up/to climb (a set of stairs)", in which 上 is read nobo 下さる (kudasaru) : "to give [to the speaker as an inferior]", in which 下 is read kuda 下りる (oriru) : "to get off/to descend", in which 下 is read o 下がる (sagaru) : "to dangle", in which 下 is read sa
Another example includes a common verb with different meanings based on the okurigana: 話す (hanasu) : "to speak/to talk". Example: ちゃんと話す方がいい。(chanto hanasu hou ga ii), meaning "It's better if you speak correctly." 話し (hanashi) : noun form of the verb hanasu, "to speak". Example: 話し言葉と書き言葉 (hanashi kotoba to kaki kotoba), meaning "spoken words and written words". 話 (hanashi) : noun, meaning "a story" or "a talk". Example: 話はいかが？ (hanashi wa ikaga?), meaning "How about a story?"
While the Japanese Ministry of Education prescribes rules on how to use okurigana, in practice there is much variation, particularly in older texts and online. As an example, the standard spelling of the word kuregata is 暮れ方, but it will sometimes be seen as 暮方.