The transformations in which *Kannon 観音 appears in order to save sentient beings. The term is frequently used in Japanese scholarly writings to refer to any deities treated as forms of the manifestations of Kannon, except for *Shōkannon 聖観音, the basic form of Kannon. The term may be used more narrowly to refer to the forms of Kannon (apart from Shōkannon) that came to be worshipped in Japan before the formal introduction of Tendai 天台 and Shingon 真言 sects, Esoteric Buddhism mikkyō 密教 in the early 9th century. It is commonly used to describe Kannon in supernatural forms (i.e. multiple arms and heads) such as *Jūichimen Kannon 十一面観音 (Eleven-headed Kannon), *Senju Kannon 千手観音 (Thousand-armed Kannon), *Fukūkenjaku Kannon 不空羂索観音, and *Nyoirin Kannon 如意輪観音, etc., even though some of these have standard iconographic forms (one head, two arms) as well . The idea of transformation is associated with the idea of incarnations or avatars, such as Shōtoku Taishi (see *Shōtoku Taishizō 聖徳太子像; 574-622) being considered an incarnation of Kannon (or of *Shaka 釈迦), as well as with the idea of grouping deities in families and counting one deity as an emanation of another, according to which Kannon is seen as an extension of *Amida 阿弥陀, for example.