East Asian Buddhism) has a total of 253 rules for bhikkhus (though the overall structure is the same). These differences arose from the systematization and historical development of doctrines and monasticism in the centuries after the death of the Buddha. The Abhidhamma-pitaka contains "a restatement of the doctrine of the Buddha in strictly formalized language." Its texts present a new method, the Abhidhamma method, which attempts to build a single consistent philosophical system (in contrast with the suttas, which present numerous teachings given by the Buddha to particular individuals according to their needs). Because the Abhidhamma focuses on analyzing the internal lived experience of beings and the intentional structure of consciousness, it has often been compared to a kind of phenomenological psychology by numerous modern scholars such as Nyanaponika, Bhikkhu Bodhi and Alexander Piatigorsky. The Theravāda school has traditionally held the doctrinal position that the canonical Abhidhamma Pitaka was actually taught by the Buddha himself. Modern scholarship in contrast, has generally held that the Abhidhamma texts date from the 3rd century BCE onwards. However some scholars, such as Frauwallner, also hold that the early Abhidhamma texts developed out of exegetical and catechetical work which made use of doctrinal lists which can be seen in the suttas, called matikas. Non-canonical literature There are numerous Theravāda works which are important for the tradition even though they are not part of the Tipiṭaka. Perhaps the most important texts apart from the Tipiṭaka are the works of the influential scholar Buddhaghosa (4th–5th century CE), known for his Pāli commentaries (which were based on older Sri Lankan commentaries of the Mahavihara tradition). He is also the author of a very important compendium of Theravāda doctrine, the Visuddhimagga. Other figures like Dhammapala and Buddhadatta also wrote Theravāda commentaries and other works in Pali during the time of Buddhaghosa. While these texts do not have the same scriptural authority in Theravāda as the Tipiṭaka, they remain influential works for the exegesis of the Tipiṭaka. An important genre of Theravādin literature is shorter handbooks and summaries, which serve as introductions and study guides for the larger commentaries. Two of the more influential summaries are Sariputta Thera's Pālimuttakavinayavinicchayasaṅgaha, a summary of Buddhaghosa's Vinaya commentary and Anuruddha's Abhidhammaṭṭhasaṅgaha (a "Manual of Abhidhamma"). Throughout the history of Theravāda, Theravāda monks also produced other works of Pāli literature such as historical chronicles (like the Dipavamsa and the Mahavamsa), hagiographies, poetry, Pāli grammars,