"Kanji" is main characters for Japanese which typically have meanings and two sounds. The total number of Kanji usually used is over 3,000. Kanji was originated from Chinese characters and had been modified and simplified in Japan for a long time.
There are also about 80 characters, so called "Hiragana", each expresses just one sound and has a soft shape. Kanji is mainly used for nouns and beginning portion of verbs while Hiragana is used for other parts including last portion of verbs. Japanese sentences typically consist of Kanji in 30% and Hiragana in 70%. There is one more character set, called "Katakana", which is another notation of Hiragana. Katakana has exactly same sound of Hiragana and a little hard shape and is used to express exported words from other countries based on their sounds.
I describe an example of struggle history for non-alphabetical character set in messaging system.