Rōshi (老師) (Chinese pinyin: Lǎoshī, Sanskrit: ṛṣi) is a Japanese honorific title used in Zen Buddhism that literally means "old teacher" or "elder master" and usually denotes the person who gives spiritual guidance to a Zen sangha. Despite the literal meaning, the title has nothing to do with the actual age of the individual who receives it and is used to indicate respect and veneration.
The title is generally granted to an individual who has realized a great understanding of the Dharma, and most rōshi have undergone many years of arduous training under a master. Only a rōshi may certify another as a rōshi. In the Rinzai school of Zen, a monastic becomes a rōshi when they have received inka shōmei, indicating they have completed kōan study and received Dharma transmission from their master. In the Sōtō school of Zen, a person becomes the equivalent of rōshi when they have received the title of shike from the Sōtō school. In the Sanbō Kyōdan school of Zen a lay disciple becomes a rōshi when they have received inka, indicating they have passed the kōan curriculum and received Dharma transmission. In all cases the title of rōshi indicates the person has met the teaching standards and become an independent teacher. Most Zen communities in the United States confer the title in line with the protocol related to their Japanese Zen roots, and in most instances it is used synonymously with the term Zen master.
Chinese Chán Buddhism uses the semantically related title Shīfu (師父, literally "master father" or "father of masters", or 師傅, literally "master teacher" or "teacher of masters"; both pronounced shīfu) for an honorific title for highest masters, but it also may be used for respectful address to monks and nuns generally.
Stuart Lachs has argued that Zen institutions in the West have often attributed a mythic status to the title Rōshi with harmful consequences:
"The idea and ritual of Dharma transmission rather than the meaning or content of that transmission, becomes the prominent and meaningful fact. Zen elevates its leaders to super-human status, then emphasizes that we should be obedient and subservient to a powerful and supremely accomplished authority figure, precisely because he is powerful and supremely accomplished. Is it any wonder that the inevitable abuses that we have seen for the last thirty years should follow?"
- Richard Baker and the Myth of the Zen Roshi by Stuart Lachs, 2002, 
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