無量壽經優婆提舍願生偈註 1.91

1.91

Question: How much time is called 'one thought'? Answer: A hundred and one arisings and ceasings is called a kṣaṇa; sixty kṣaṇas are called a single thought (eka-citta). What is called 'thought' here does not take this measurement of time; it simply means keeping Amitābha Buddha in mind, either in his general marks or specific marks, following the conditions of contemplation with no other thoughts in mind. A succession of ten such thoughts is called 'ten recitations.' Merely calling the name is also like this.