Bright Sword

The Bright Sword is a treasure in. It is actually a yellow sword-shaped.

Serene Shores
There is a Bright Sword stuck inside of a large sand heap covering the Water's Edge base near the center of the overworld, a bit farther northwest. To collect this treasure, you must dig it out, then throw 1 Pikmin at it.

Cavern for a King
There are two Bright Swords inside of a Man-at-Legs in the center of sublevel 9 of the Cavern for a King, alongside two Heroic Swords. To collect them, you must first defeat the Man-at-Legs, then throw 1 Blue Pikmin at each treasure.