Pure Land Buddhism (Jodo Buddhism) is a variety of popular Buddhism developed in China and imported to Japan in the 12th century. There are several varieties of Pure Land Buddhism, but the common denominator is the assumption that the world is so corrupt that the believer cannot attain salvation in the Pure Land (also called the Western Paradise) by his or her own efforts. Instead, the aid of one who has attained salvation must be sought. In some sects, a phrase is repeated over and over to secure help; in others, the preferred phrase need only be said once in a lifetime. The popular appeal of this variety of Buddhism, compared to earlier sects which demanded decades of study, was tremendous.