Essays / MEXT Japanese scholarships Need Ideas [5]

hi everybody, i just filled the application for the 2014 mext japan scholarship , i just need a little help and some idea about the 3 followings essays , should it be long ? or just signifient enough, should it comport an introduction ? because i got straight ! :

*Field of study you specialized in at high school.
*What kind of field are you planning to study in Japan?.
*What kind of impression do you have of Japan?
*Description of desired employment to be taken up after returning home.