This sword looks like a saber with small holes in it's handle. These holes are so that when swung, the sword emits different sound frequencies, but make it very hard to handle due to the wind streams. A bard with Exotic Weapon Proficiency (Bladesong sword) can use it as an instrument for his bardic music, as long as he has enough Perform (Bladesong sword) ranks. You can use the Weapon Finesse feat to apply your Dexterity modifier instead of your Strength modifier to attack rolls with a Bladesong sword sized for you, even though it isn’t a light weapon for you.