Quick to see the opening, and already moving before anyone else decides.
Rat is the branch that starts the cycle — the hour just past midnight, the season just past the solstice. In a chart it reads as quick timing: you notice the opening before anyone else does, and you are already moving while others are still deciding whether to. People experience this as sharpness, sometimes read as opportunism when it's really just speed. It shows up loudest wherever it sits in your four pillars — a year Rat carries it into your public reputation, a day Rat makes it your own temperament.