“The minimum effective dose (MED) is defined simply: the smallest dose that will produce a desired outcome… To boil water, the MED is 212° F (100° C) at standard air pressure. Boiled is boiled. Higher temperatures will not make it ‘more boiled.’ Higher temperatures just consume more resources that could be used for something else more productive.” ―Tim Ferriss, The 4-Hour Body

What does boiling water have to do with learning kanji? Simple: just as you only need a certain temperature to boil water, you only need to know a finite number of high-frequency kanji to read blogs, manga, books, magazines, newspapers, etc. Though there are approximately 50,000 Chinese characters listed in the dai kan-wa jiten (大漢和辞典, だいかんわじてん, “The Great Han–Japanese Dictionary”), the Japanese Ministry of Education limits the number of “common use” characters, jouyou kanji (常用漢字, じょうようかんじ), to only 2,136. Most publications limit themselves to just these characters, using kana instead of kanji for any word with characters outside the list. This means that the Japanese learner’s “Kanji MED” is 2,136, not 50,000! Phew!

Focus on the Highest-Frequency Kanji First

While you need to learn all 2,136 jouyou kanji to be literate, you can cut down your initial workload by employing the 80-20 Rule and focusing first on the highest-frequency characters.

Consider, for example, the following kanji usage statistics for Japanese Wikipedia:

  • 50% of Japanese Wikipedia is written with just 200 kanji.
  • 75% of Japanese Wikipedia is written with just 500 kanji.

There are many kanji frequency lists available online, but most are based on newspapers, meaning that the rankings tend to be skewed toward specialized vocabulary used in business, finance, geography, crime reporting, etc.

To create a less biased frequency list, a Reviewing the Kanji forum member named Shang decided to use the whole of Japanese Wikipedia as the text corpus. That’s some serious data to crunch! Fortunately, Shang was kind enough to compile and share the data in this nifty Google Doc that includes KANJIDIC reference numbers, as well as Remembering the Kanji frame numbers and keywords. You rock Shang!

But Realize that “Most Common” Doesn’t Always Mean “Most Useful”

Though it makes sense to focus on the highest-frequency words and characters in the beginning, it doesn’t mean that you shouldn’t also spend time on vocabulary outside of these lists that fits your personal interests and unique learning needs. The guiding light throughout your Japanese journey should be interest.

No matter how frequent a given set of words or characters are, they won’t stick if you’re studying them in isolation or using materials that bore you to tears. Frequency lists are a useful reference point, but the actual learning should come from:

  • Audio, video, and text content you love.
  • Materials you will be willing to repeat again and again.