The Moon is eighteen, unable to see; the Sun is nineteen, everything lit. A naked child rides a white horse carrying a red banner, sunflowers in a row behind, a sun with a face overhead. It answers the Moon point for point: the Moon's path winds, the Sun's child rides straight out; the Moon's creatures are dog, wolf and crayfish, the Sun's is one horse without a saddle. The mechanism: under the sun nothing is distorted; what you see is what's there. Nineteen is nine past ten — the Hermit's clarity, without needing to climb the mountain.
Where you'll recognise it: things finally clear, being able to be open, a childlike simple gladness, the moments you notice you no longer have to prove anything. This card is about brightness — not everything going your way, but no shadow to hide in.
Running well, the Sun is the most direct state there is: clear, warm, alive, seen and unafraid of it. Stuck, its problem is too bright — sunburn: so pleased you can't see others, so open you leave no room, or assuming a clear sky means no more night. The child has no saddle: the joy is real, and it doesn't steer itself.