We will not talk about the history of Japan because you can search it online, so we will go directly to their language.
(disclaimer notice: Information / guides that will be written here is based on my understanding and may have conflict to other guides on how to understand Japanese language)
First we will talk about their writting system. They have 3 writing system, and a extra.
The 3 Writing systems are
Hiragana - these are the curve style writing system they have, and primarily their own language. ex. is flower = hana (はな）
Katakana - these are those sharp style writing which is primarily used for borrowed words. example is messenger which directly translate to this word メッセージ。
Kanji - literally means "Chinese Characters", so yes, that why chinese characters can also be read by japanese (majority of it) because that too, is also included in their language. So if you see this word 時間 which translate to english as TIME. both in japanese and in chinese, but the only diffirence will be how to pronounce it.
4 (extra). Romaji - this is the readable version for the foreigners to quickly understand the word when reading japanese words.
Ex.
(hiragana) はな
(kanji) 花
(katakana) ハナ
all of these are read as "hana".
the only problem with these is that we can only know the exact meaning of the word, if we see the kanji it represents or the whole sentence it want to say. Because, just like any other languages, a single word can mean many things.
Romaji version is typically used for teaching foreigners the Japanese language, other than that, you may not be able to see it in other places since, when using borrowed words, they use the katakana version when writing.
Lets try to construct a sentence, to see the difference of the writing system.
In english sentence equivalent
" My Name is ________ . "
Hiragana version.
わたし の なまえ は ＿＿＿＿＿ です。
Kanji version.
私 の 名前 は ＿＿＿＿＿＿です。
Katakana version (not used, but just to present how it is written)
ワタシ ノ ナマエ ハ ＿＿＿＿＿＿＿ デス。
Thats all for now. :D