Chinese vocabulary has exerted an enormous influence on the Japanese language. At the time of their first contact, the Japanese language had no writing system, while the Chinese had a written language and a great deal of academic information, providing new concepts along with Chinese words to express them. Chinese became the language of science, learning and religion. The earliest written language to be used in Japan was , which has come to be called ''kanbun'' in this context. The ''kanbun'' writing system essentially required every literate Japanese to be competent in written Chinese, although it is unlikely that many Japanese people were then fluent in spoken Chinese. Chinese pronunciation was approximated in words borrowed from Chinese into Japanese; this Sino-Japanese vocabulary is still an important component of the Japanese language.
Sino-Japanese and On'yomi
The term kango is usually identified with ''on'yomi'' , a system of pronouncing Chinese characters in a way that at one stage approximated the original Chinese. On'yomi is also known as the 'Sino-Japanese reading', and is opposed to ''kun'yomi'' under which Chinese characters are assigned to, and read as, native Japanese vocabulary.
However, there are cases where the distinction between on'yomi and kun'yomi does not correspond to etymological origin. Chinese characters created in Japan, called , normally only have kun'yomi, but some kokuji have on'yomi. One such character is 働 , which was given the on'yomi ''dō'' when used in compounds with other characters, e.g. 労働 ''rōdō'' . The character 腺 , which has the on'yomi ''sen'' was intentionally created as a 'kango' and does not have a kun'yomi at all. Although not originating in Chinese, both of these are regarded as 'Sino-Japanese'.
By the same token, kun-yomi is not an absolute guarantee that a word is native Japanese. There are a few Japanese words that, although they appear to have originated in borrowings from Chinese, have such a long history in the Japanese language that they are regarded as native and are thus treated as kun'yomi, e.g., 馬 ''uma'' "horse" and 梅 ''ume''. These words are not regarded as belonging to the Sino-Japanese vocabulary.
Words 'Made in Japan'
While much Sino-Japanese vocabulary was borrowed from Chinese, a considerable amount was created by the Japanese themselves as they coined new words using Sino-Japanese forms. These are known as ''wasei kango'' .
The best-known example is the prolific numbers of kango coined during the era on the model of Classical Chinese to translate modern concepts imported from the West. These words include 科学 ''kagaku'' , 社会 ''shakai'' , 自動車 ''jidōsha'' , 電話 ''denwa'' and a host of other basic words. The use of Chinese elements to form words in Japanese is akin to the way that English words are formed using Greek and Latin elements, such as the English word "telephone", which was created from the Greek morphemes ''tele'' and ''phone'' . The Japanese formation 電話 ''denwa'' means 'electric' + 'talk'. Much of this vocabulary was borrowed back into Chinese around the turn of the 20th century and is now used indistinguishably from native Chinese vocabulary. Many of these words have also been borrowed into and .
Many Japanese-created kango refer to uniquely Japanese concepts. Examples include '''' , '''' , ''haiku'' , ''geisha'' , '''' , ''matcha'' , ''sencha'' , ''washi'' , '''' , '''' , '''' , '''' , '''' , ''seppuku'' , and ''manga'' .
Another miscellaneous group of words were coined from Japanese phrases or crossed over from ''kun'yomi'' to ''on'yomi''. Examples include ''henji'' , ''rippuku'' , ''shukka'' , and ''ninja'' . In Chinese, the same combinations of characters are often meaningless or have a different meaning. Even a humble expression like ''gohan'' is a pseudo-''kango'' and not found in Chinese. One interesting example that gives itself away as a Japanese coinage is ''kaisatsu-guchi'' , meaning the ticket barrier at a railway station.
Finally, quite a few words appear to be Sino-Japanese but are varied in origin, written with ''ateji'' — kanji assigned without regard for etymology. In many cases, the characters were chosen only to indicate pronunciation. For example, ''sewa'' is written 世話, using the ''on'yomi'' "se" + "wa" ; although this word is not Sino-Japanese but a native Japanese word believed to derive from ''sewashii'', meaning 'busy' or 'troublesome'; the written form "世話" is simply an attempt to assign plausible-looking characters pronounced "se" and "wa." Other ''ateji'' of this type include 面倒 ''mendō'' and 野暮 ''yabo'' .
Phonetic equivalencies between Mandarin and ''On'yomi''
At first glance, the ''on'yomi'' of many Sino-Japanese words do not resemble the modern Standard Mandarin Chinese pronunciations at all. However, the observed differences are due to the nature and history of the two languages involved, as well as natural linguistic change over time. Sino-Japanese is very important for comparative linguists as it provides a large amount of evidence for the reconstruction of Middle Chinese.
The following is a rough guide to equivalencies between modern Chinese words and modern Sino-Japanese ''on'yomi'' readings.
Unless otherwise noted, in the list below, sounds shown in quotation marks, such as "h" or "g", refer to Hanyu pinyin romanization for Mandarin Chinese and Hepburn romanization for Japanese. Symbols shown within square brackets, such as or , indicate .
# A major sound-shift has occurred in since the time of modern contact with the West. Namely, the sounds written in Pinyin as or , when immediately preceding an "i", "y" or "ü" sound, became "j" or "q" . This change is called palatalization. As a result, ''Peking'' changed to ''Běijīng'', and ''Chungking'' to ''Chóngqìng''. This shift did not occur in Sino-Japanese. Thus, Mandarin '''' corresponds to Japanese ''ki''. In some other Chinese dialects/languages, it is still pronounced as 'ki'. For example, 氣 in Southern Min is khì . This is similar to the way the Latin
# The Japanese language does not have an "-ng" or syllable endings, which is very common in Chinese. This sound was borrowed as either /i/ or /u/. The combinations /au/ and /eu/ later became "ō" and "yō", respectively, in Japanese. Thus, the Mandarin reading of "Tokyo" is ''Dōngjīng''; this corresponds to Japanese '''', with sound history for 京 being supposed approximately *kia? -> kyau -> kyō . Another example is 京城, former name for Seoul, which is ''Keijō'' in Japanese and ''Gyeongsang'' in . 京 is read "kei" in this case.
# The vowels of Chinese sometimes correspond to Sino-Japanese in an apparently haphazard fashion. However, Mandarin "ao" often corresponds to Japanese "ō" , and Chinese empty often corresponds to in Japanese.
# The distinction between voiced and unvoiced consonants has been lost in modern Mandarin and many other Chinese languages. The key exception is in . The Shanghainese voiced consonants match the Japanese ''go-on'' readings nearly perfectly in terms of voicing. For example, 葡萄 is pronounced "budo" in Shanghainese and "budō" in Japanese , but "pútáo" in Mandarin. Incidentally, the rising tone of the Mandarin syllables may reflect the earlier voiced quality of the initial consonants.
# In modern Mandarin, all syllables end either in a vowel or in one of a small number of consonant sounds: "n", "ng", or occasionally "r". However, premodern Chinese, like several modern Chinese dialects , allowed several other final consonants including , , , and , and these are preserved in Sino-Japanese . However, because Japanese phonology does not allow these consonants to appear at the end of a syllable either, they are usually followed in Sino-Japanese by an additional "i" or "u" vowel. As a result, a one-syllable word in Chinese can become two syllables in Sino-Japanese. For example, Mandarin ''tiě'' corresponds to Japanese ''tetsu'' . This is still pronounced with a final in Cantonese: . Another example is Mandarin ''guó'' , from older ''guk'' , corresponding to Japanese ''koku''.
#The consonant "f" in Mandarin corresponds to both "h" and "b" in Japanese. This is due to changes in Chinese phonology; the Japanese language has preserved the older forms to some extent, but has gone through phonological shifts itself. Thus, Mandarin ''Fó'' corresponds to Japanese ''butsu'' ; both derive from the archaic Chinese . In modern Southern Min Chinese, this character is still pronounced as . This pattern appears in Latin and English as well: Latin ''frater'' corresponds to English ''brother'' although both words are derived from the same Indo-European root. Another example is the change of the initial f to h in certain verbs in Spanish when compared to Latin, thus ''hacer'' from ''facere''.
# In addition, bilabial consonants have gone through numerous phonological shifts in both Chinese and Japanese since the time of borrowing. For example, 八 is "ba" in modern Mandarin, but "hachi" in modern Japanese. This suggests that the "h" consonant in modern Japanese was closer to "p" in archaic Japanese.
# More complex is the archaic dento-labial nasal sound: The character 武 was pronounced "mvu" in Middle Chinese. The sound is approximated in the Japanese pronunciations "bu" and "mu". However, that sound no longer exists in most modern Chinese dialects, except Southern Min "bú", and the character 武 is pronounced "wǔ" in Mandarin, "mo" in Cantonese and "vu" in Hakka.
# The modern Mandarin consonant "r" usually corresponds to "ny" or "ni" in Japanese. At the time of borrowing, characters such as 人 and 日 , which have an initial "r" sound in modern Mandarin, began with a palatal nasal consonant closely approximating and "gn" and "?". Thus Mandarin ''Rìběn'' corresponds to Japanese ''Nippon''. This is also why the character 人 is pronounced "nin" in some contexts, as in "ningen" — approximating the character's Middle Chinese pronunciation — and "jin" in others, such as "gaijin" — approximating its more modern pronunciation. In Wu dialects, including Shanghainese, 人 and 二 are still pronounced "nin" and "ni", respectively. In Southern Min , 人 is "j?n" which is practically identical to Japanese On'yomi.
# In Middle Chinese, 五 and similar characters were pronounced with a velar nasal consonant, "ng" , as its initial. This is no longer true in modern Mandarin, but it remains the case in other Chinese dialects such as Cantonese and Shanghainese. Japanese approximates the Middle Chinese "ng" with "g" or "go"; thus 五 becomes "go". In Southern Min, it is pronounced as 'go' while in Fuzhou dialect it is still pronounced "ngu".
# The Mandarin "hu" consonant sound does not exist in Japanese and is usually omitted, whereas the Mandarin "l" sound becomes "r" in Japanese. Thus, Mandarin '''' corresponds to Japanese ''?baku'', and ''Rúlái'' to ''Nyorai''.
# Mandarin "h" will often correspond to "k" in Japanese. Old Japanese lacked an sound; Modern Japanese is derived from Old Japanese , which descended in most cases from a Proto- */p/. Mandarin "z" will often correspond to Japanese "j"; these are also changes in Chinese. Thus, Mandarin '''' corresponds to Japanese ''kanji'', and ''hànwén'' to ''kanbun''.
Chart of correspondences
* MC: Middle Chinese
* Go: 呉音 ''Go-on'', from the Southern and Northern Dynasties China or Baekje Korea during the and . Go means
* Kan: 漢音 ''Kan-on'', from the Tang Dynasty during the to 9th century
* → →
* → or , in Tō-on
* → → → ,
* → , ,
* → , ,