Combat Focus( Player's Handbook II, p. 87)
[Combat Form, Fighter Bonus Feat]
The way of the warrior requires more than simple, brute strength. Some warriors bring their minds to such keen focus during the heat of battle that they can attain superhuman levels of endurance, perception, and mental toughness. Through intense mental exercise and training, you learn to enter a state of perfect martial clarity.
In battle, you push aside the chaos of the fight and attain a focused state that grants you a keen, clear picture of the battle. Fear and pain ebb away as you focus solely on defeating your enemy. The first time you make a successful attack during an encounter, you gain your combat focus. In this state, your mind and body become one, allowing you to overcome mundane physical limits. You can maintain your combat focus for 10 rounds after entering it, +1 additional round per combat form feat you possess aside from this one. You can only gain your combat focus once per encounter. While you are maintaining your combat focus, you gain a +2 bonus on Will saves. If you have three or more combat form feats, this bonus increases to +4.
A fighter can select Combat Focus as one of his fighter bonus feats.