Although each character in Hiragana has an equivalent in Katakana, Hiragana is the most common script, with cursive rather than block-like letter forms. Kanji characters are used to write root words. Katakana is mostly used to represent “foreign” words, that is, words imported from languages other than Japanese.
Kanji has tens of thousands of characters, but the number commonly used has declined steadily over the years. Now only about 3500 are frequently used, although the average Japanese writer has a vocabulary of about 2000 Kanji characters. Nonetheless, computer systems must support more than 7000 characters in accordance with the Japan Industry Standard (JIS) requirements. In addition, there are about 170 Hiragana and Katakana characters. On average, 55% of Japanese text is Hiragana, 35% Kanji, and 10% Katakana. Arabic numerals and Roman letters are also present in Japanese text.
Although completely avoiding the use of Kanji is possible, most Japanese readers find a text that is composed without any Kanji hard to understand.