To be a teacher, you must be able to write a good hand. What is the best pen for hard pen calligraphy?

The most popular and commonly used hard pen writing tools for China calligraphy teachers are pens and gel pens, followed by limited pencils and dying ballpoint pens. I have been using pens in the following order since school: pencil (kindergarten), pen (primary school), ballpoint pen (junior high school), gel pen (high school university), pen+gel pen (university to date).