Zen Koans: Verbal symbols calculated to provoke an ontological breach in our carapace of ignorance. [GTUFS: TreasuresB, Treasures of Buddhism]

Formulas both meaningless and explosive, and intended to shatter the shell of mental habits that obstruct the vision of the Real. [GTUFS: SurveyME, Confessional Speculation: Intentions and Impasses]

The koan is a formula by intention absurd, destined to bring about a kind of liberating rupture in the mind of the person meditating on it, the mind in this instance being considered with regard to its hardness and blindness. [GTUFS: TreasuresB, Remarks on the Enigma of the Koan]