A friend of mine told me that, in Japanese, if they have to write a kanji that is complicated or has too strokes, they just write it in hiragana to save time. Of course, when they write the clean version of the notes they use kanji.

If you search this word "学生 ノート" meaning "student's note" in Google Image Search, you get this result. https://www.google.co.jp/search?q=%E3%83%8E%E3%83%BC%E3%83%88%E3%80%80%E5%AD%A6%E7%94%9F&espv=210&es_sm=91&source=lnms&tbm=isch&sa=X&ei=nEoPU_O-O4yClQWu5oHQAQ&ved=0CAkQ_AUoAQ&biw=1387&bih=708

I think it's a writing habits. We started learning to write with 漢字 when we were small . So now we have been accustomed to write with it. In chinese, "take notes in classes" means "记课堂笔记".

Hey dsaki, I just wondered how taking notes worked for japanese and chinese becausei of their writting system, which seems to take more time the with western alphabet. So, how they would note what the teacher is saying fast enough...that's the question, especially in the chinese case, which there is no hiragana. Do they use hanzi or pinyin, how this works? And thank you for your answer.

This question is interesing :D even though I don't understand what do you want to know. I mean, we take notes as other people, just write words @@　by the way, japanese is not only using 漢字, they use hiragana and katakana too.