ならの 公園に 住む しかの 数が、 今までで 一番 多く なりました。
人が やさいを あげるので、 しかの 赤ちゃんが たくさん 生まれます。
車の じこも あるので、 みんな 心配して います。
Why six school grades, and not N5–N1?
Because that is how Japanese children learn to read. Japan's Ministry of Education fixes exactly which character belongs to which grade — so "grade 3" is a boundary you can verify, not a feeling. Every article here is machine-checked: if a single character sits above its grade, it is not published.
The result: you never hit a character you have not learned. That is the whole reason this product exists.