560. This #kanjipuzzle is about evolution. Start with one character, add a few strokes, and get another, then repeat. 一 -> ? -> ? -> ? -> ? -> 豊

Answer:

一  ICHI, ITSU, hito(tsu) - one

二  NI, futa(tsu), futa - two

コ  Katakana "Ko"

口  KOU, kuchi - mouth

豆  TOU, ZU, mame - bean, pea

豊  HOU, yuta(ka) - abundant, rich