Rōshi (老師?), is a Japanese honorific title meaning "old [venerable] master. " It may be a contraction of rōdaishūshi, "ancient master of the tradition. "
In Zen Buddhism (especially Rinzai), this title is mostly conferred on monks who have realized a great understanding of the dharma, and who have had a direct experience of it, called satori, i.e., who have awakened to their true nature and realized themselves through the Zen path.
They can also be laypeople, and also women engaged in this path.
On the Zen path, the Rōshi is the one who guides his or her students to awakening following the example of the historical Buddha in a sitting meditation position called zazen (just sitting), having attained awakening under the Bodhi Tree more than 2500 years ago.
Today, this term tends to become commonplace. However, the title Rōshi in the West can sometimes lead to confusion and controversy.
In the past, the title of Rōshi was difficult to obtain. It was usually people (not the master himself) who used this title for a master whose daily life proved a real practice of enlightenment, and who was also able to lead others to the same experience.
In the Rinzai school, becoming a Rōshi required many years of practice under the guidance of another Rōshi who will have been able to certify his student's awakening during the dokusan.
Deep awakening first had to be attested to by the future Rōshi's master, which is done by the awarding of an "authentication seal" (jap. inka-shomei or inkajo). There frequently followed many years of maturation of this awakening through "dharma battles" (jap. hossen) with other masters.
In the Sōtō school, one becomes a master by going through the process of shihō, through a series of ordination ceremonies with one's own master who will then attest to mastery of the precepts and authentic transmission of the dharma.
Through this, the recipient is empowered to teach and to ascend to the office of abbot of a monastery of the school.
The title of Rōshi today
While true Rōshi can still be found today, they are becoming rarer, and the conditions for obtaining the title have become more relaxed. As a result, the term tends to become commonplace and to be used to address a Zen monk simply to show respect for his or her position or age in sangha zazen practice and in his or her clerical hierarchy.
The use of the title Rōshi by Westerners sometimes leads to confusion and controversy. They often attribute a mythical status to the title, which can have harmful consequences.