怪人二十面相

This is a classic children’s detective book from the 1930s. 二十面相 is a gentleman thief and a master of disguise. He dislikes harming people, he politely sends letters advising when and where he will strike; and while stealing the item, before he makes his getaway, he takes a moment to stand talking to his victim explaining exactly how he pulled off the caper. Opposing him are the famous detective Akechi Kogorou and his precocious sidekick, the boy Kobayashi. The plot is fast-paced, and full of disguises, traps, gadgets, and chases. Is anyone who they say they are?

Reviews here and there from advanced readers estimate this as suitable for N3. But IMO whether this is actually true or not is going to depend on your goals, and whether you want to be reading intensively or extensively. If you thrive on challenge and you’re willing to put in lots of effort looking things up, then yes, you probably can do this at that level. However, if the goal is “comprehensible input” with minimal dictionary or grammar look ups, then this is a book for a considerably more experienced reader.

The basic sentence structure isn’t terribly challenging. This is not one of those books with long delicate sentences which require deep mastery of grammar to unwind. The writing here is straightforward. N1 grammar points appear, but you can look them up and keep going on, because the overall sentence structure as a whole will probably be in a comfortable N3-ish framework. It was much easier to understand than 銀河鉄道の夜. However, some characters have really thick/slurred character speech.

The challenge is vocabulary. To put the amount of vocabulary into context: by page 80 I had already looked up more new words than I did for all 160 pages of コンビニ人間, or all 360 pages of ペンギン・ハイウエイ. The settings and situations kept changing (because of exciting plot twists), so most of the words/expressions that were new to me were used only once. Furthermore, this is a detective story, so details matter. Often by a book’s halfway point I can use the dictionary much less, but the constant setting changes, continuing high frequency of new words, and the high comprehension necessary to follow a detective story made that difficult here until the very end. This was written in the 1930s, so the word choices are different from a modern book, including words for clothing, objects, and jobs which are no longer common today. Some words are spelled differently. There’s a lot of hiragana, and I had to look up many words which I would have easily figured out if the kanji had been used instead. I read a paper version so looking up all these words was especially painful. I’d suggest reading this book digitally instead.