First thing with Japanese, there are 3 different writing system for the language.
1) Hiragana
2) Katakana
3) Kanji
HiraganaThe primary function of the Hiragana script is the expression of native Japanese words. It is also the only script used for particles and copulas, and all inflectional endings and verb stems.
Example:
oniisan (elder brother)
kagi (key)
KatakanaKatakana symbols are used mainly for representing foreign words. Modern Japanese contains a great number of words borrowed from European languages, especially English. These borrowed words are written in Katakana symbols.
Example:
Amerika (America)
Shingapo--ru (Singapore)
KanjiThis would be the chinese characters that we see, except that, they are not pronounced the way we do in chinese.
Example:
the chinese words
xian1 sheng1 could mean
teacher senseithe chinese words
da4 xue2 university dai gakuso far so good?
Romanji is not part of the writing system tho...