Choose a double weapon you are proficient with.  You can wield the double weapon as either a two-handed or one-handed weapon.

Prerequisite: Weapon Focus (in the chosen double weapon), base attack bonus +5.

Benefit: By employing a number of different stances and techniques, you can wield a double weapon as a one-handed weapon. At the start of your turn, you decide whether or not you are going to wield the double weapon as a one-handed or two-handed weapon. When you wield it as a one-handed weapon, your other hand is free, and you cannot use the weapon as a double weapon. If the two ends of the double weapon are different, you must choose which end you are using when this feat is being used.  You can take the feat Weapon Specialization in the double weapon even if you have no levels in fighter.

Special: You may select this feat more than once.  Its effects do not stack.  Each time you select this feat it applies to a different double weapon.

Note: This feat does not apply to quarterstaffs.  There is a separate feat called Quarterstaff Master that applies to quarterstaffs.