commonly pronounced both as ton-jiru (mixed on-kun) and buta-jiru (kun-kun), with ton somewhat more common nationally. Inconsistencies abound—for example gyū-niku "beef" and yō-niku "mutton" have on-on readings, but buta-niku "pork" and tori-niku "poultry" have kun-on readings. The main guideline is that a single kanji followed by okurigana (hiragana characters that are part of the word)—as used in native verbs and adjectives—always indicates kun'yomi, while kanji compounds (kango) usually use on'yomi, which is usually kan-on; however, other on'yomi are also common, and kun'yomi are also commonly used in kango. For a kanji in isolation without okurigana, it is typically read using their kun'yomi, though there are numerous exceptions. For example, "iron" is usually read with the on'yomi tetsu rather than the kun'yomi kurogane. Chinese on'yomi which are not the common kan-on reading are a frequent cause of difficulty or mistakes when encountering unfamiliar words or for inexperienced readers, though skilled natives will recognize the word; a good example is (go-on), where is usually instead read as kai. Okurigana (送り仮名) are used with kun'yomi to mark the inflected ending of a native verb or adjective, or by convention. Note that Japanese verbs and adjectives are closed class, and do not generally admit new words (borrowed Chinese vocabulary, which are nouns, can form verbs by adding at the end, and adjectives via -no or -na, but cannot become native Japanese vocabulary, which inflect). For example: aka-i "red", atara-shii "new", mi-ru "(to) see". Okurigana can be used to indicate which kun'yomi to use, as in ta-beru versus ku-u (casual), both meaning "(to) eat", but this is not always sufficient, as in , which may be read as a-ku or hira-ku, both meaning "(to) open". is a particularly complicated example, with multiple kun and on'yomi—see okurigana: 生 for details. Okurigana is also used for some nouns and adverbs, as in nasake "sympathy", kanarazu "invariably", but not for kane "money", for instance. Okurigana is an important aspect of kanji usage in Japanese; see that article for more information on kun'yomi orthography Kanji occurring in are generally read using on'yomi, especially for four-character compounds (yojijukugo). Though again, exceptions abound, for example, jōhō "information", gakkō "school", and shinkansen "bullet train" all follow this pattern. This isolated kanji versus compound distinction gives words for similar concepts completely different pronunciations. "north" and "east" use the kun'yomi kita and higashi, being stand-alone characters, but "northeast", as a compound, uses the on'yomi