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".
Written Chinese
For over two thousand years, the prevailing written standard was a vocabulary and syntax rooted in Chinese as spoken around the time of Confucius (about 500 BC), called Classical Chinese, or 文言文 "wényánwén". Over the centuries, Classical Chinese gradually acquired some of its grammar and character senses from the various dialects. This accretion was generally slow and minor; however, by the 20th century, Classical Chinese was distinctly different from any contemporary dialect, and had to be learned separately. Once learned, it was a common medium for communication between people speaking different dialects, many of which were mutually unintelligible by the end of the first millennium AD. A Mandarin speaker might say "yī", a Cantonese "yāt", a Shanghainese "iq", and a Hokkien "chit", but all four will understand the character <> to mean "one".