The Japanese writing system was introduced into Japan by the Chinese around the middle of the 6th century AD. The Chinese language is very different to Japanese in structure so the writing system was gradually adapted to fit the structure of the Japanese language. There are now three scripts that make up the Japanese writing system (four if you include roman script): kanji; hiragana and katakana. The latter two are known collectively as kana.
I think there are better methods for learning kanji, but this isn't bad. And it's kind of helpful sometimes to see the evolution of kanji and how they relate to the objects they describe.
Reading this was definitely helpful in my current understanding of Chinese characters. Learning stroke order, or at least being able to recognise it, is extremely helpful to me now living in China.