The name “Taigu” (大愚), associated with Ryōkan, is his Dharma name and literally means “Great Fool” or “Big Fool.” It is composed of two Chinese characters: 大 (tai or dai), meaning “great” or “big,” and 愚 (gu), meaning “fool” or “foolishness.” This translation is not a casual nickname but a deliberate spiritual designation, chosen and carried within the Zen monastic context. The apparent self-deprecation of the term is therefore not an insult but a pointer toward a particular spiritual stance.

Within the Zen tradition, this “Great Fool” does not signify stupidity or dullness, but rather a profound spiritual simplicity and a freedom from worldly cleverness. The name suggests a state of childlike innocence and a letting go of the pride that comes from intellectual sophistication. In this sense, “foolishness” becomes a symbol of having stepped beyond conventional judgments of wise and foolish, success and failure. Ryōkan’s adoption of “Taigu” as his Dharma name thus reflects an aspiration to live in radical simplicity and authenticity, unburdened by the need to appear clever in the eyes of the world.