composed of two (or more) characters, with the meaning associated with the combination. For example, is composed of (person radical) plus (action), hence "action of a person, work". This is in contrast to kanji generally, which are overwhelmingly phono-semantic compounds. This difference is because kokuji were coined to express Japanese words, so borrowing existing (Chinese) readings could not express these—combining existing characters to logically express the meaning was the simplest way to achieve this. Other illustrative examples (below) include sakaki tree, formed as "tree" and "god", literally "divine tree", and tsuji "crossroads, street" formed as () "road" and "cross", hence "cross-road". In terms of meanings, these are especially for natural phenomena (esp. flora and fauna species), including a very large number of fish, such as (sardine), (codfish), (seaperch), and (sillago), and trees, such as (evergreen oak), (Japanese cedar), (birch, maple) and (spindle tree). In other cases they refer to specifically Japanese abstract concepts, everyday words (like , "crossroads", see above), or later technical coinages (such as , "gland", see above). There are hundreds of kokuji in existence. Many are rarely used, but a number have become commonly used components of the written Japanese language. These include the following: Jōyō kanji has about nine kokuji; there is some dispute over classification, but generally includes these: dō, hatara(ku) "work", the most commonly used kokuji, used in the fundamental verb , included in elementary texts and on the Proficiency Test N5. ko(mu), used in the fundamental verb nio(u), used in common verb hatake "field of crops" sen, "gland" tōge "mountain pass" waku, "frame" hei, "wall" shibo(ru), "to squeeze" (disputed; see below); jinmeiyō kanji sakaki "tree, genus Cleyera" tsuji "crossroads, street" monme (unit of weight) Hyōgaiji: shitsuke "training, rearing (an animal, a child)" Some of these characters (for example, , "gland") have been introduced to China. In some cases the Chinese reading is the inferred Chinese reading, interpreting the character as a phono-semantic compound (as in how on readings are sometimes assigned to these characters in Chinese), while in other cases (such as ), the Japanese on reading is borrowed (in general this differs from the modern Chinese pronunciation of this phonetic). Similar coinages occurred to a more limited extent in Korea and Vietnam. Historically, some kokuji date back to very early Japanese writing, being found in the Man'yōshū, for example— iwashi "sardine" dates to the Nara period (8th century)—while they have continued to