Random Kanji Box

[Kei]

I've been looking at the random kanji box at the left side of the screen. It has helped me learn a few kanji. Easy ones at least. But I noticed that many have katakana and hiragana pronunciation, but some only have katakana. Is there a reason to that? I haven't learned katakana yet so I was wondering.

[Daisuke]

'Kun' readings (chinese) are written in katakana, and 'on' readings (japanese) are written in hiragana.

[Kei]

Ok I need to study more then to understand all this.

[Spaztick]

Some only have on readings, because some are never used by themselves.