Kan Seifu is the only one in the world who uses hard glass (heat-resistant glass) to create the flameworked glass pen from holder to its tip. Each glass pen is carefully handcrafted with 2200 °F burning flame. Over 60 years, he has been creating glass pens that have strong and durable tip and enable smooth writing as fountain pen. His glass pen is capable of drawing a very fine line, and furthermore, it prevents the ink from dripping.

He always says, "I would like to support people who contribute to world peace." He sends his glass pen to writers, politicians, artists, scholars and professors to show his appreciation to them. He also donates his work to charity such as Kyoto Shimbun Newspaper, Yomiuri Shimbun, Japan Guide Dog Association and other welfare organization. He is willing to continue supporting them as much as he could.

The difference between Hard glass and Soft glass

The hard glass, also known as heat-resistant glass requires twice as much heat as soft glass, and for instance it is used in coffee syphon. Kan Seifu's glass pen is heat-resistant, chemical-resistant, and abrasion-resistant. It even prevents wearing which was drawback of the traditional glass pen.