The present paper is the first of a series of textual studies on Sthiramati’s Tattvārthā on Abhidharmakośa(bhāṣya) 4.35–44. The series will provide a Sanskrit text and an annotated Japanese translation of the Tattvārthā together with texts and translations of Vasubandhu's Abhidharmakośabhāṣya and Saṃghabhadra’s *Nyāyānusāriṇī 順正理論 . The *Nyāyānusāriṇī, the earliest available commentary on the Abhidharmakośabhāṣya, is frequently quoted by Sthiramati explicitly and silently. Therefore it is one of the most important witnesses for understanding the Tattvārthā. Abhidharmakośa 4.35–44 deals with the attainment and the abandonment of the three kinds of the unmanifest (avijñapti), i.e., restraint (saṃvara), non-restraint (asaṃvara), and neither-restraint-nor-non-restraint (naiva-saṃvara-nāsaṃvara). This paper focusses on Abhidharmakośa 4.35 and its commentaries, which mainly discuss the scope of the three kinds of restraint (i.e. prātimokṣasaṃvara, dhyānasaṃvara and anāsravasaṃvara).