The time to learn hard pen calligraphy varies from person to person. Generally speaking, it may take 1 to 3 years to learn according to one's calligraphy foundation and learning ability. Among them, strokes need 20 class hours, radicals need 50 class hours, structural rules need 50 class hours, and the remaining 30 class hours are composition.
It should be noted that the time here is only an estimate, and the actual time required may be different due to the individual's learning progress and understanding ability.