kana 仮名

In Japanese, the kana 仮名 are the hiragana ひらがな and the katakana カタカナ syllabaries, or the characters (letters) that compose them. The kana, together with the kanji 漢字, would form the entirety of the Japanese alphabet.

Unlike kanji characters, which can be read differently depending on the word, the kana characters are always read the same way (except for when はへを are pronounced wa, e and o). Because of this, the kana are normally used to explain how a kanji is supposed to be read.

A way this is done is through the furigana 振り仮名, which is written beside the kanji, and another is the okurigana 送り仮名, which is written after to distinguish between multiple standard readings.

Besides that, certain diacritics called dakuten 濁点 can change the pronunciation of a kana. For example: ka か to ga が.

For reference, a romaji chart:

Moraic Kana

The kana are often said to represent syllables, however, they represent moras, an unit of time.

Generally, a single written kana represents one mora of time, meaning two kana take twice as long to pronounce than one, and four take twice as long as it takes to pronounce two. The term compound kana is used to refer to syllables of one mora written with two or three kana, one normal-sized kana followed by small kana.

Furthermore, two kana may represent a single syllable. For example: kou こう is one syllable whose vowel takes two mora to pronounce. This is called a long vowel, and is sometimes represented by the prolonged sound mark ー, like this: koo コー.

Iteration

The symbols ゝゞヽヾ are iteration marks for the kana; they work similar to how 々 works for kanji, although the kana iteration marks are not as common.