How does the Golden Lute (the weapon) work?

You attack by moving next to an enemy. The Lute deals one point of damage.

Below, "adjacent" means in a neighboring tile horizontally or vertically, not diagonally.

• If you move out of a tile adjacent to an enemy, it deals damage to the enemy.
• If you move into a tile adjacent to an enemy, it deals damage to them (including move directly away from the enemy).
• If you attack an enemy in the traditional sense, by moving into them, it does not deal damage.

Source: Once you beat the Necrodancer, you unlock a character who wields the Golden Lute, so you can practice with it in the lobby.