Mobile Bulwark (3.5e Maneuver)

You adjust your grip on the shield to allow you to use your greatsword and shield at the same time.

While you are in this stance, bucklers have no penalty to attack rolls for attacking with two-handed weapons or weapons in your off hand.

In addition you may use two-handed weapons or fight with two weapons while using a light or heavy shield. You take a -1 to attack rolls when doing so.

Finally if you are using a tower shield, you do not take the -2 penalty to attack rolls. You may shield bash with a tower shield, dealing 1d8 points of damage with a 20/x2 critical.