As I have discussed before, the Japanese sentence is composed of Hiragana, Katakana, and Kanji. So, it is better to learn these three-writing systems of Japanese. Before we will proceed in studying Kanji, let’s learn another writing system of Japanese sentence structure.
ふりがな (振り仮名Furigana) or よみがな (読み仮名Yomigana) is a reading guide for Kanji used for learner’s materials for children or foreigners, Kanji’s that are rare or have multiple meanings, signage or name of railway stations. ふりがな is usually written in Hiragana but in some cases, it may be written in Katakana.
ふりがな are used for Japanese children who still have limited Kanji knowledge or cannot read Kanji yet but can understand the meaning when written in Hiragana or Katakana. Most Manga especially in Shonen (spelled as Shounen when writing it in Hiragana or Kanji しょうねん (少年)) and Shojo (spelled as Shoujo in Hiragana or Kanji しょうじょ(少女)) manga used ふりがな written above Kanji. Others use ふりがな in slang words, especially writers, for the readers to understand it properly.
Let’s check the sample below:
I have this magazine I bought last 2019. It's J-Generation magazine. At the back of the Magazine, there is a question SMAPとは何か？ (What is SMAP?) Underneath, there are Kanji’s written which means ‘end of national Idol’. As you have noticed, the ふりがな written above the Kanji is in Katakana.
アイドル (aidoru) means Idol. This is one example where the ふりがな is written in Katakana.