Shields Shall Be Splintered

A player can elect to sacrifice an equipped shield to reduce all damage from an attack to 1, or to pass a single saving throw.  

If a character has a magic shield equipped, the shield is not destroyed but its magical bonus is instead permanently reduced by one. If this reduces the shield's bonus to +0, it becomes non magical but continues to be masterwork in quality.

Shields Shall Be Splintered

By Fortune and Fate lostgrail