Obstacles (Tib. བར་ཆད་, barché; Wyl. bar chad) on the spiritual path are often classified into outer, inner and secret categories (Tib. ཆི་ནང་གསང་བའི་བར་ཆད་, Wyl. chi nang gsang ba'i bar chad). Another way of looking at obstacles is called the four maras or four demons.
- Outer obstacles (Tib. ཕྱིའི་བར་ཆད་, Wyl. phyi'i bar chad) are disturbances of the four primary elements (such as earthquakes, floods, fires, hurricanes, etc.); the machinations of the mara of the Lord of Death and the mara of the aggregates; disease, famine and warfare; and the dread of rebirth, death, and the bardo.
- Inner obstacles (Tib. ནག་གི་བར་ཆད་, Wyl. nag gi bar chad) are imbalances in the psycho-physical system of channels, wind-energies and essences which give rise to all kinds of sickness; the machinations of the mara of destructive emotions; and the deluded perceptions of desire, anger, and dullness.
- Secret or innermost obstacles (Tib. གསང་བའི་བར་ཆད་, Wyl. gsang ba'i bar chad) are the obstacles of the deluded concepts of perceiver and perceived; the machinations of the mara of the son of the gods; and the hindrance for the state of omniscience.
- Tulku Urgyen Rinpoche, Repeating the Words of the Buddha