The word kanji is the Japanese version of the Chinese word hànzì, which means Han characters. Han refers to the Han Dynasty and is the name used by the Chinese for themselves.
When the Japanese adopted Chinese characters to write the Japanese language they also borrowed many Chinese words. Today about half the vocabulary of Japanese comes from Chinese and Japanese kanji are use to represent both Sino-Japanese words and native Japanese words with the same meaning.
Kokoro means mind or heart
Wrote kanji by brush and ink in the traditional way is called Sho-Do Japanese calligraphy