Hi there! I got interested in Yojijukugo (四字熟語) which are words or idioms consisting for 4 characters. Idiomatic ones like 海千山千 are pretty difficult to guestsimate what they mean, since usually there is a story involved (see details below):
“Ocean-thousand, mountain-thousand” means “a sly old fox” or someone who has had all sorts of experience in life so that they can handle, or wiggle out of, any difficult situations through cunning alone. This meaning derives from an old saying that a snake lives in the ocean for a thousand years and in the mountains for another thousand years before it turns into a dragon. Hence a sly, worldly-wise person is referred to as one who has spent “a thousand years in the ocean and another thousand in the mountains”.
Non-idiomatic ones ‘make more sense’ if I can say it like that. An example would be 日米関係, which are the Japan–US relations.
Reading a bit more, it turns out that there are thousands of such characters, also 5- and 6-kanji expressions that are super obscure. There are lists for children to see what they are ‘expected’ to know.
It’s hard to get a grip on to what extent they are more of a linguistic flourish that makes sense for advanced studies or very specific texts like politics or religion and to what extent they might occur in daily life.
To get a qualitative idea, I took this list, which is a random heap of 15k words from internet and media vocabulary (not exactly comparable to aozora, especially in terms of literariness but more on everyday words). And filtered the 4+ character expressions. As you can see, many of them are proper nouns of companies and universities, political and geographical expressions. But still, whereas “経済企画庁” might not be amazingly useful, knowing the characters for one of the most read newspapers, 毎日新聞, or a war of historical importance, 太平洋戦争, might be quite useful (in the ballpark of WK words).
I actually heard 一生懸命 in the wild, so there’s even that.
Below I attached a csv if anybody wants to include them into Anki or anything. The first column, rank, shows where in the 15k words it appears. At WK Level 60 I would say it would be good to know all the expressions that are up to rank 10000 and the others contingent on circumstances (if you fly out to Narita, make sure to know 成田空港).
|1921||37.63||国務大臣||Minister of State|
|3396||19.04||朝日新聞||Asahi Shimbun (newspaper)|
|5653||9.72||読売新聞||Yomiuri Shimbun (newspaper)|
|5713||9.57||東京大学||University of Tokyo|
|6964||7.16||日本銀行||Bank of Japan|
|8245||5.59||産経新聞||Sankei Shimbun (newspaper)|
|8277||5.55||試行錯誤||Trial and error|
|8450||5.39||共同通信||Kyodo News (news agency); joint communication|
|9248||4.69||創価学会||Soka Gakkai (Buddhist movement)|
|10137||4.09||日本共産党||Japan Communist Party|
|10387||3.95||年末年始||Year-end and New Year|
|10486||3.90||日経新聞||Nikkei Shimbun (newspaper)|
|10513||3.88||岩波書店||Iwanami Shoten (publishing house)|
|11008||3.62||政務次官||Vice-Minister for Political Affairs|
|11196||3.53||歌舞伎町||Kabukicho (entertainment district in Shinjuku)|
|11212||3.53||道路公団||Japan Highway Public Corporation|
|12026||3.18||朝日新聞社||Asahi Shimbun (newspaper)|
|12723||2.90||経済学部||Department of Economics|
|12734||2.90||経済企画庁||Economic Planning Agency (until 2001)|
|12821||2.86||法務大臣||Minister of Justice|
|12852||2.86||会計検査院||Board of Audit|
|13815||2.55||農林水産省||Ministry of Agriculture, Forestry and Fishery (MAFF)|
|13863||2.53||生年月日||Date of Birth|
|13884||2.53||日本経済新聞||Nihon Keizai Shimbun (newspaper)|
|14438||2.38||小中学校||Elementary and junior high school|
|14500||2.37||中国共産党||Chinese Communist Party|
rank, occ, expression, translation 1425, 52.46, 株式会社, stock company 1921, 37.63, 国務大臣, Minister of State 3104, 21.30, 一生懸命, very hard 3396, 19.04, 朝日新聞, Asahi Shimbun (newspaper) 3458, 18.67, 都道府県, Prefecture 5575, 9.89, 毎日新聞, Mainichi (newspaper) 5653, 9.72, 読売新聞, Yomiuri Shimbun (newspaper) 5713, 9.57, 東京大学, University of Tokyo 5879, 9.19, 中途半端, halfway 6549, 7.86, 地方自治体, Local government 6670, 7.65, 靖国神社, Yasukuni Shrine 6964, 7.16, 日本銀行, Bank of Japan 7612, 6.28, 朝鮮半島, Korean Peninsula 8085, 5.74, 義務教育, Compulsory education 8245, 5.59, 産経新聞, Sankei Shimbun (newspaper) 8277, 5.55, 試行錯誤, Trial and error 8405, 5.44, 情報処理, Information processing 8450, 5.39, 共同通信, Kyodo News (news agency); joint communication 9139, 4.79, 最高裁判所, Supreme Court 9248, 4.69, 創価学会, Soka Gakkai (Buddhist movement) 10016, 4.16, 無理矢理, forcibly 10137, 4.09, 日本共産党, Japan Communist Party 10173, 4.07, 三位一体, Trinity 10387, 3.95, 年末年始, Year-end and New Year 10431, 3.93, 早稲田大学, Waseda University 10486, 3.90, 日経新聞, Nikkei Shimbun (newspaper) 10513, 3.88, 岩波書店, Iwanami Shoten (publishing house) 10639, 3.80, 京都大学, Kyoto University 10999, 3.62, 地方裁判所, District Court 11008, 3.62, 政務次官, Vice-Minister for Political Affairs 11171, 3.54, 大学院生, Graduate student 11196, 3.53, 歌舞伎町, Kabukicho (entertainment district in Shinjuku) 11212, 3.53, 道路公団, Japan Highway Public Corporation 11449, 3.42, 修学旅行, School trip 11923, 3.22, 二酸化炭素, Carbon dioxide 12026, 3.18, 朝日新聞社, Asahi Shimbun (newspaper) 12574, 2.96, 太平洋戦争, Pacific War 12613, 2.94, 第一人者, Leading figures 12723, 2.90, 経済学部, Department of Economics 12734, 2.90, 経済企画庁, Economic Planning Agency (until 2001) 12821, 2.86, 法務大臣, Minister of Justice 12852, 2.86, 会計検査院, Board of Audit 13231, 2.73, 明治維新, Meiji Restoration 13641, 2.60, 神戸大学, Kobe University 13815, 2.55, 農林水産省, Ministry of Agriculture, Forestry and Fishery (MAFF) 13863, 2.53, 生年月日, Date of Birth 13884, 2.53, 日本経済新聞,Nihon Keizai Shimbun (newspaper) 14385, 2.39, 自分勝手, Selfish 14438, 2.38, 小中学校, Elementary and junior high school 14484, 2.37, 慶應義塾, Keio University 14500, 2.37, 中国共産党, Chinese Communist Party 14631, 2.33, 成田空港, Narita Airport 14641, 2.33, 一目瞭然, obvious 14643, 2.33, 文藝春秋, Bungeishunju (publisher)
If you have any corrections for the list or your own experience how and when they are useful and how to assess the children idiomatic compounds, let me know!
P.S.: I meant to add the reading to the list, but then had to leave. Using the 10ten browser surely helps greatly with this list!