◇ Just read — no move neededCannons fade, horses grow
The cannon lives on OTHER pieces: every capture needs a screen, and screens are pieces. As the board empties, screens vanish and the cannon dims — the proverb says 炮怕空膛, the cannon fears the hollow board. The horse is the opposite: fewer pieces means fewer hobbled legs. When you must trade in the late game, give up the cannon, keep the horse.