Too Suhk Sool - see below for standard Romanization and other goodies...
TU SEOK SUL : 투석술 : 投石術 : "stone-throwing technique" - a basic self-defense measure, taken from village protection strategy where the stone walls marking the village boundary could be used as ammunition by anyone caring to defend the village when attacked by outsiders (an old Korean custom was, upon returning home, to add to the village walls any suitable stones/rocks one found while venturing out for hunting or other travel)