1162. What character can be added to both of these characters to give other characters? 其_ -> _更

Answer:

其  shi, so - that

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

Add 石:其+石 石+更 

石  SEKI, SHAKU, ishi - stone

碁  GO - go (board game)

硬  KOU, kata(i) - hard, firm