Woah, that’s a bold claim you are making! Don’t you know that the kkkbears pride themselves in the bear book being one of the easiest for learners? I hope this isn’t a denial of the “the supremacy of くまクマ熊ベアー and the genius of くまなの” 
Speaking of 赤川 次郎, it seems that most of their books aren’t terribly difficult. The obvious one for me would be 吸血鬼はお年ごろ | L26 because 吸血鬼 but the high volume count terrifies me. If I read just one volume, it’s over, I’m reading them all. So, I think I’m going to have to put that one off for a while. 
