Direction Sense

A character with this proficiency has an innate sense of direction. By concentrating for 1d6 rounds, the character can try to determine the direction the party is headed. If the check fails but is less than 20, the character errs by 90 degrees. If a 20 is rolled, the direction chosen is exactly opposite the true heading. (The DM rolls the check. Furthermore, when traveling in the wilderness, a character with direction sense has the chance of becoming lost reduced by 5%.

Dwarven Direction Sense Proficiency

Dwarves receive a +2 bonus to their modifier when using their direction sense underground. They may use it above ground, but at a -2 penalty to Wisdom. Sundered dwarves should reverse these modifiers to reflect their fear of the underground.

[Player's Handbook]
[Complete Book of Dwarves]