Dore kanji ga ichiban muzukashii desu ka?
Shitsumon arigatou!

Watashitati ga tukau kanji no naka dewa,
鬱 (utsu, depression, 29 kaku(strokes)!!) ga ichiban muzukashii desu.
Muzukashii kanji desu ga, yoku tsukawareru ji desu.
ex)クリスマスに鬱になる。
Kurisumasu ni utsu ni naru.
(I get depressed in Christmas.)
Demo, motto muzukashii kanji mo arimasu.
Watashitati ga tukawanai kanji no naka dewa,
84 kaku no kono kanji ga ichiban muzukashii desu.
http://ja.wikipedia.org/wiki/%E3%81%9F%E3%81%84%E3%81%A8