It took this author about 20 minutes of daily study for two years to become literate in Japanese, but there are many people who have been in Japan for longer, who have long given up on it being too hard. Certain people after living in Japan still believe that Japan should turn to an all-phonetic writing system, as have Korea and Vietnam, who formerly used chinese characters. In any case, these politically-principled people are still illiterate in Japanese.
The Japanese writing system is made up of three scripts, all used together. The following is a short history of the development of Japanese writing. The examples are for reference only. If you are studying, you'll learn them when it comes to that point in the textbook.
Originally, Japanese was not a written language. From about the 15th century, the Japanese elite learned to read Chinese, and with the limited phonemes that the Japanese language had,many of the sounds became simplified. (Puronaunshieishon beri difikaruto.) These Chinese-based pronunciations form the modern on readings (音読み). Chinese influence in Japan conincided with different periods of increased trade and cultural exchange, during which the Chinese language was undergoing shifts in pronunciation. Hence a single Kanji might be read differently in depending on the era in which a certain Chinese word was introduced into Japanese. Thankfully for the student, the vast majority of kanji readings are from the Kan era in China, hence the name Kanji, which means "Kan Writing."
In addition, most Kanji also have a kun reading, which is the native Japanese word that had the same meaning as the Kanji. Many Kanji also have more than one kun reading, depending on the specific meaning of the word. Take 上, for example.
Japanese, unlike Classical Chinese, requires conjugation of adjectives and verbs. The key innovation to writing Japanese, came when scribes started borrowing Chinese characters to represent sound, disregarding the original meaning. The earliest such usage was in the Manyoshu 万葉集, a collection of Japanese poetry compiled in the 7th and 8th centuries.
Originally, characters were used in their full form, so depending on the context, 天 could be pronounced ten and mean "heaven," or te, without the original meaning. Eventually, for ease of reading, the kanji were written in an abbreviated form when they were only meant to indicate sound. However, there came to be two ways of simplifying:
Katakana (片仮名), an angular script developed to match the angularity of standard Kanji. It was used for annotating religious texts and for legal documents. In modern times, it's used to write foreign words and onomatopeoia, or to give emphasis to a word, much like how italics are used in English.
Hiragana (平仮名), a flowing script developed for use with cursive Kanji, used with calligraphy, poetry. In modern times, it's used to write conjugations and native Japanese words.A complete list of the Kana and the Kanji from which they originated is here.
The conjugations written at the end of verbs are called Okurigana. They serve to clarify the meaning and clarification of the Kanji preceding it. For example:
The modern ordering of the Kana is a, i, u, e, o order, which I learned as a song that goes a, ka, sa, ta, na, ha, ma, ya, ra, wa, with the tune going do-re-mi-fa-so, so-fa-mi-re-do, and then with wo and n at the end.
In old dictionaries, and certain situations where it's cool to appear "retro," Japanese use i, ro, ha, ni, ho order, with all the kana arranged so that they are used exactly once to spell out a 48-syllable poem on the transience of worldly existence, a Japanese translation of the Sanskrit poem "Sabbe Sankhara Anicca." This was before TV or video games, so people with means had much more time than modern people to think and reflect on such things.
Japanese was written vertically in lines running top to bottom, with
successive lines following to the left. This is still a
common direction for many popular novels and magazines. Horizontal
writing was originally done from left to right as well; essentially a
special case of vertical writing, where the column height was one
character. In modern times, however, almost all horizontal writing goes
from left to right. The only common exception is writing on the sides
of vehicles and ships, where characters are written on so that they are read from the front to the back.