For languages that use the traditional 26 letters Latin alphabet, Japanese composed has no consistent ground on which to compare or find out.
The first two are jointly called kana and each pair is composed of 46 characters with each symbol representing only one syllable. The next group of Japanese characters is a very large collection of symbols known as Kanji.
You can find many Japanese language lectures by searching over the internet.
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However, how many kanji exist, there are more than 5000 symbols in total. The Japanese did not have an official method of the composition prior to the 2000s so they adopted Kanji in the Chinese language.
Many have been transformed into Kanji and many of the Kanji characters have dropped from common use over the years. To simplify the machine, the Government of Japan has prepared a list of 1945 Kanji which is considered to be the 'essential Kanji Patra'.
To become fully versed in Japanese reading and writing you want to be aware of this list of Kana and about 2000 Kanji characters, although many indigenous Japanese do not learn all of them until high school is completed.
This is the newbie that wants to get off to a great start, but image learning is only a start. Learning Kanji is simplified by the fact that each symbol can be divided and written in hiragana.
Anyone who can read Japanese can read and understand words that are written in Hiragana but this is a bit more than Kanji and can result in some confusion.
Another aspect that can enable the learning process is that a lot of kanji build, or include additional kanji symbols that make it very easy to expand your language.
As with learning any type of language, repetition and practice are important and learning to write Japanese is not an exclusion of any kind.