We can classify the function of KANJI in Japanese into 2 groups; word level & sentence level. First, there are 2 functions in word level of KANJI; function of word-formation, and function of ideography. function of word-formation in MEIJI is different from the modern one. In MEIJI, it is usually made up of two-words KANGO. but, nowadays, two-words KANGOs join together and make 3 or 4-words KANGOs. By the way, because of the simple structure of syllable in Japanese, there are many homonyms, which are identified by KANJI. This is exactly the function of ideography. Sentence level is composed of 2 functions; expression of BUNSETU and variable expressing measures. Unless Japanese is composed of only KANA, we can know where to divide sentences by using KANJI. In addion, we can distinguish the grammatical role of each word by using KANJI and KANA together. As you see, KANJI plays important role in Japanese.