Character amnesia
It is difficult to establish exactly how many different Chinese characters are in use today; the new HSK, a widely used proficiency test for Standard Chinese as a second language, tests over 2,600 different characters, whilst in 1988 the People's Republic of China published the "List of Commonly Used Characters in Modern Chinese" which contains 7,000 different characters. In Japan, where a smaller set of characters are in general usage, the Japanese Ministry of Education prescribes the teaching of 2,136 kanji in primary and secondary school in a list called the jōyō kanji, meaning "regular-use Chinese characters".
Chinese dictionary
The second system of dictionary organization is by recurring graphic components or radicals. The famous 100–121 CE "Shuowen Jiezi" (說文解字 "Explaining Simple and Analyzing Compound Characters") arranged characters through a system of 540 "bushou" (部首 "section header") radicals. The 543 CE "Yupian" (玉篇 "Jade Chapters"), from the Liang Dynasty, rearranged them into 542. The 1615 CE "Zihui" (字彙 "Character Glossary"), edited by Mei Yingzuo (梅膺祚) during the Ming Dynasty, simplified the 540 "Shuowen Jiezi" radicals to 214. It also originated the "radical-stroke" scheme of ordering characters on the number of residual graphic strokes besides the radical. The 1627 "Zhengzitong" (正字通 "Correct Character Mastery") also used 214. The 1716 CE "Kangxi Zidian" (康熙字典 "Kangxi Dictionary"), compiled under the Kangxi Emperor of the Qing Dynasty, became the standard dictionary for Chinese characters, and popularized the system of 214 radicals. As most Chinese characters are semantic-phonetic ones (形聲字), the radical method is usually effective, thus it continues to be widely used in the present day. However, sometimes the radical of a character is not obvious. To compensate this, a "Chart of Characters that Are Difficult to Look up" (難檢字表), arranged by the number of strokes of the characters, is usually provided.