一手
yī shoǔ · HSK 7
by oneself
✋ 一手 = one (一) + hand (手); single-handed means by yourself, your own mastery
一 means one and 手 means hand. Something done with one hand, single-handedly, is done by oneself without outside help, and a trade you handle solo points to real skill or mastery.
一 — single horizontal stroke
一 is one of the simplest pictographs in Chinese, depicting a single horizontal line to represent the number one. It has retained essentially the same form since oracle bone script over 3,000 years ago. By extension it also means 'first,' 'whole,' or 'same.'
手 — pictograph of a hand with five fingers
手 is a pictograph showing an open hand with fingers and a wrist. Early bronze and oracle bone forms clearly depict five splayed fingers, which simplified over time into the modern shape. It keeps its original meaning of 'hand' and also serves as a radical in many characters related to hand actions.