打開
だかい · dakai · JLPT N1 · noun
solution
🔑 打 (strike) + 開 (open) = strike through a stuck situation to open it: breakthrough
打 means strike or hit, and 開 means open. Together they describe forcing open a blocked situation, which is why the word means solution or breakthrough.
打 — hand radical 扌 + nail 丁
打 combines the hand radical 扌 (action with the hand) with 丁 (originally a nail), suggesting striking or hitting with the hand. 丁 also serves as a phonetic hint in older readings. The meaning broadened from 'to strike' to a general verb for many hand-based actions, like 打电话 'make a phone call'.