일필휘지 一筆揮之

The idiom is composed of 'One' (一), 'Brush' (筆), 'Brandish/Swing' (揮), and 'It' (之), literally meaning to finish it with one stroke. Historically, it refers to the legendary calligraphers and literati of the Tang Dynasty who, in a state of total immersion, produced masterpieces in a single sitting. This term does not merely celebrate speed; it signifies the culmination of years of practice and inner discipline that finally explodes into creative energy. In a modern context, this 'one-stroke' philosophy is often seen in high-performance arts and music, where a performer's long-term training manifests as a single, powerful, and unstoppable display of genius.