Does the average native Japanese reader know how to pronounce a majority of Kanji found in books?

Question

After studying Japanese for quite a while and having read many books (maybe over 50-60 over a bunch of different genres), despite the fact I generally have tried to learn the readings of most words I come across, I always find myself discovering new words everyday whose pronunciation I don't know. Part of the time I can guess the reading since I know the common readings of the Kanji involved, but often not.

Nevertheless, even without understanding every reading and looking up every word, I still can understand things enough to follow the story.

My question is: Do most adult Japanese natives who read books really know each and every reading of every word they come across, or is there frequently times when they aren't sure? I'm sure some academic/intellectual type people who read very often might know nearly all of the readings, but I'm more curious about the average person who reads books off and on.

Part of the mystery to me is how one would learn all these readings. Most adult books don't have that much Furigana, and many of the more advanced words I am talking about wouldn't be heard frequently, if ever, in daily life. I just have a hard time believing adult readers would frequently look up Kanji readings, and instead would just aim to read such that they understand the overall flow of what is going on.

One example of one such books with a great many difficult words (for me) is this book, which is what I would call hardcore fantasy: https://www.amazon.co.jp/図書館の魔女-上-高田-大介/dp/4062182025

EDIT:　As there was some discussion of the above-referenced book with difficult Japanese, I'll give a link to a review I wrote for it here.

Answer 1

As long as you are reading common novels, you can generally believe that average Japanese speakers can pronounce almost all kanji that don't come with with furigana (But as for 図書館の魔女, I don't know, since I had no way to review its contents. According to the book reviews, it seems that the book contains rather difficult words.)

But there are some "well-known reading mistakes" like 未曾有（×みぞゆう）、踏襲（×ふしゅう）、既出（×がいしゅつ）、and so on and on. This page has many examples.

• 誤読の世界: http://homepage2.nifty.com/tei-tagami/newpage5.html

It contains some words that are no longer common, so you don't have to memorize them all. But if you are not familiar with most of the words in this list, it means you still need some more work building up your vocabulary.

And it's hard to tell how often I, for example, come across uncertain words... For typical novels that are not "hardcore fantasy", I think it should be one word or two per book chapter, but I may be skipping difficult words almost unconsciously.

People make errors guessing the readings of place or person names all the time.

Answer 2

As far as it concerns Kanjis used in daily newspapers and magazines and modern literatures, I think most of Japanese don’t have much problem in reading and pronouncing them. But it applies only to 現代文 – modern Japanese language.

But when it comes to 文語文– written in classic writing styles i.e., the style used in Meiji period (1868 -1912) and earlier than Meiji era, the story is different.

Let me give you an ad hoc example:

There is the following sentence in page 230 in ”蹇蹇録（けんけんろく）- Memoire on the political situation around 日清戦争 (the Shino-Japan War -1894-95) and his diplopmatic achievement” at hand, which was written by 陸奥宗光 - Mutsu Munemitsu (1844 -1897) , Minister of Foreign Affairs at that time, and published in 1895 by Ministry of Foreign Affairs.

"陛下の御稜威に頼り開戦以来今日に至るまで海に陸に到る処、捷を発して以て我が国の武威を輝かし、また第三国より干渉の端を啓きたるも時に及びてこれを擺脱（はいだつ）してその甚だしきに至らしめず、以て今日に至ると言えども、本件の結果如何によりては実に我が国将来の隆替に関する所あれば、今この異変の局を収むるには宜しく慎重に熟籌（じゅくちゅう）し、時を鑑み機を察し、以てこれに適応するの計を講ぜざるべからざるはまた言を待たざるなり."

Rough translation:

In virtue of the influence of His Majesty, we made glorious victories both on the sea and ground ever since we declared the war (against China). Though we had interventions by the third party countries during this period, we managed to solve the problems skillfully thus far. However, depending on the future turn of this issue, it can bring the serious consequence on the future of our country. We need to be really considerate in dealing with the present situation we are now facing. It is needless to say that we should be shrewd and flexible to meet the difficulty lest we should lose the opportunity and timing.

I don’t know three words (擺脱、熟籌、隆替) in the above Japanese sentence, and there are three other words I don’t understand in the same page.

First of all, I'm curious to know what percent of Japanese contemporaries and how many native Japanese users of this site know how to read the word of the title of the book, "蹇蹇録," what it means, and can pronounce it correctly.

I suspect there won't be so many Japanese today who know that the word, “蹇蹇 (けんけん)” came from the line of 蹇卦 (Saigua), “蹇蹇匪躬 (sai-sai-fei-gong) – to commit loyalty to the king on the cost of his own life” appearing in Chinese classic, “易経 – the Book of Changes.”

As a pre-war generation, we learned 文語文 including both 漢文 and 古文 much harder than today’s younger generations. Still I found six unlearned words in a single page (Page 230) of a writing published only 121 years ago, with which few had difficulty in reading then.

I’m also reading now ”臨済碌 – Analects of Zen priest, Rinzai” at hand, published by 1989 from Iwanami Shoten. My comprehension level of 漢字 in 読み下し文 - Japanese way of reading Chinese text - without referring to annotations is 60 per cent or so of it at the most,

So my answer to the OP's question is Yes, most Japanese people can read most of 漢字 in modern literature. But I’m very much skeptical of whether today’s contemporaries have a good command of reading of writings published in Meiji, even Taisho era, much less before then.

Answer 3

内容紹介

鍛治の里に暮らす少年キリヒトは、師の命により、大陸最古の図書館を統べるマツリカに仕えることになる。古今の書物を繙き、数多の言語を操って策を巡らせるがゆえ、「魔女」と恐れられる彼女は、自分の声をもたないうら若き少女だった。本を愛し、言葉の力を信じるすべての人に!

I guess average Japanese readers don't know how to pronounce 繙き (especially if without the help from the context) but still, they know majority of pronunciation. These two facts can coexist, right?

FYI ひもとく itself is not so uncommon, but is usually spelt as 紐解く or in hiragana.