For those people that don't know a Koan is a story or a sentence a Zen Buddhist Master uses to help liberate a student from concepts. Some of the more famous koans are "What is the sound of one hand clapping?" or "If a tree falls in the woods does it make a sound?". One of my favorite ones is "Before your parents were born what did your face look like?" but they don't work for everyone. They are seen in the West as being nonsense things without meaning. However they do have a meaning and there is an answer to the question. When you find the answer you'll be liberated.

There is a story of a Zen student that his teacher gave him a koan and after a while of being told his answers are wrong the student gives up being a Zen Monk. He soon becomes a farmer and one day digging in his land the hoe hits a rock. The thunderous sound awoken the farmer and he gained enlightenment while remembering the koan. So they are interesting tools a teacher uses to liberate minds.

Sitting in bed I remember a silly question, "Can God make a mountain so heavy he can't lift it?" I wonder if that is a koan as well. It can help liberate a person's mind of concepts. I wonder if anyone attained awakening after hearing that.