A tea ceremony master, known as "Chadō no Sōshū (茶道の宗主)" or "Chajin (茶人)" in Japanese, is an individual who has attained a high level of proficiency and mastery in the art of Japanese tea ceremony, also known as "Sadō" or "Chadō" (茶道).

The tea ceremony is a traditional Japanese cultural practice that involves the ceremonial preparation and presentation of matcha, a powdered green tea, in an atmosphere of tranquility and mindfulness. The tea ceremony embodies principles such as harmony, respect, purity, and tranquility.

A tea ceremony master has undergone extensive training and study in various aspects of tea ceremony, including the proper techniques for preparing and serving tea, understanding the different utensils and equipment used, mastering the traditional gestures and movements, and gaining a deep understanding of the underlying philosophy and aesthetic principles of the tea ceremony.

Tea ceremony masters often dedicate many years to their training and may have received certifications or titles from recognized tea schools or associations. They may also be involved in teaching and preserving the traditions of the tea ceremony, passing down their knowledge and skills to future generations.

Being addressed as a tea ceremony master is a mark of respect for their expertise, experience, and dedication to the art of tea ceremony.