Editing Yagura:SRD:Skills Summary (section)

======Taking 20======
Taking 20 represents putting in a great deal of effort in an attempt to make the check as "perfect as you can get". It means doing it over, and over, and over until you get it right... even if you get it wrong once or twice along the way. If you would fail the check in a way that would not allow you to retry it had you rolled a 1, you treat your 1d20 roll as if it had come up 1. Otherwise you treat your 1d20 roll as if it had come up 20. Taking this option takes 20 times as long as a normal use of the skill ability.