“世界中を転戦する日本の選手達が一堂に会す”
From Baby Steps
While studying Japanese, one of the things I learned early on was that a kanji used by itself would use its “kun” reading, and two kanji used together would use their respective “on” readings. This is a rule with many exceptions. While reading manga, I discovered many two-kanji words that used their kun readings instead. These are so widespread that I think anybody who has studied Japanese would have come across many examples of this.
However, for a long while I wasn’t aware that the opposite could happen as well i.e. a kanji by itself could use the “on” reading, even though there was already a “kun” reading available. I have to admit that this revelation blew my mind. Not only could a word be expressed by a single kanji using the “kun” reading, and a compound using the “on” reading, but once more by a single kanji using the “on” reading (actually, many words can also be written using the katakana form of the English equivalent, so in theory that’s four ways to say the same thing).
The sentence at the top from the Baby Steps manga can roughly translate as “Japanese players competing around the world meet for a short time [at the all-Japan Tennis Tournament]“. The sentence uses 会す read かいす instead of the more usual 会う read あう. I guess the former sounds more formal for example in a narration. In this case, common 会 compounds such as 会議 and 集会 aren’t suitable. Another option would have been to use 集まる or the compound 集合. Here, 集 used by itself with its “on” reading means “a collection”, and so doesn’t fit the sentence.
I guess this means that Japanese, like most languages, has a certain amount of inbuilt redundancy, allowing it to express the same concepts several ways (as the English language has words of German and French origins). However for Japanese, it’s harder to make this connection since we are taught to read single kanji and compounds differently. But once we notice that the hiragana ending of the standalone kanji is different from the expected one (“す” and not “う”), or even missing, we can infer that we should use the “on” reading.
Hiking Around Tokyo 