Restriction: The monk is not allowed to deliberately speak any lies, including bluffing, stating half-truths with the intent to deceive, exaggerating, telling white lies, and so on. This applies to all forms of communication. If presented with circumstances where telling the truth would bring harm to another, the monk remains silent. Many monks of this vow also take a vow of silence to show their commitment.
Benefit: A monk with this vow increases his ki pool by 1 ki point for every 5 monk levels (minimum +1).