Korean Seon is marked above all by its distinctive use of *hwadu* practice. A *hwadu* is a short, critical phrase such as “What is this?” that functions as the focal point of meditation, not as a riddle to be solved but as a living question that cuts through conceptual thinking. Rather than moving through a large curriculum of different cases, many Seon practitioners stay with a single *hwadu* as their lifelong gateway, returning to it again and again. This sustained focus is meant to gather the mind into a single, undivided inquiry that does not rest on intellectual understanding. In contrast to methods that emphasize detailed observation of sensations or thoughts, the primary task here is to keep this question vividly present.

Within this framework, Korean Seon places great weight on the cultivation of “great doubt.” By maintaining unbroken attention on the *hwadu*, an intense, unresolved questioning gradually forms—a kind of “doubt-mass” that pervades the practitioner’s whole being. This doubt is not skepticism in the ordinary sense, but a deep, existential wondering that refuses to be satisfied with secondhand answers. The tradition holds that when this mass of doubt reaches a critical point, it collapses in a sudden awakening, revealing one’s inherent Buddha-nature. Yet this sudden breakthrough is not seen as the end of the path; it is followed by ongoing cultivation that gradually stabilizes and embodies the insight.

Another characteristic feature of Korean Seon is its integrated approach to practice and life. Sitting meditation, walking meditation, chanting, bowing, and engagement in daily activities are not treated as separate compartments but as different expressions of the same inquiry into the *hwadu*. Monastic communities structure intensive retreat periods in which this question-centered practice is carried through day and night, yet lay practitioners are also encouraged to sustain the *hwadu* amid ordinary responsibilities. In this way, meditation is not confined to the meditation hall; the investigation is meant to permeate every gesture and circumstance.

Doctrinally and practically, this path is framed by a dynamic tension between faith and doubt, sudden awakening and gradual cultivation. Faith here means trust in the efficacy of the *hwadu* and in the possibility of awakening, while doubt functions as the sharp edge that prevents complacency and conceptual grasping. Compared with approaches that prioritize relaxation, bare attention, or systematic analysis of experience, Korean Seon presents a more question-driven, existentially charged mode of meditation. Its distinctiveness lies less in outward form and more in this inner stance: an unwavering, wholehearted inquiry that uses a single phrase to open the depths of mind.