2987. This #kanjipuzzle is about evolution. Start with one character, add a few strokes, and get another, then repeat. 一 -> ? -> ? -> ? -> ? -> ? -> ? -> 硬

一 -> 二 -> コ -> 口 -> 日 -> 由 -> 更 -> 硬

一 ICHI, ITSU, hito(tsu) - one

二 NI, futa(tsu), futa - two

コ Katakana "Ko"

口 KOU, kuchi - mouth

日 NICHI, JITSU, hi, ka - sun, day

由 YUU, YU, YUI, yoshi - reason, cause

更 KOU, sara, fu(kasu), fu(keru) - anew, again, grow late

硬 KOU, kata(i) - hard, firm