His name was Aasim bin Bahdalah Abee An-Najood Al-Asadee, and he was called Abu Bakr. He was the sheikh of the recitors in Al-Kufah after Abdulrahmaan Al-Sulamee. He excelled in both purity of language and mastery. He had the best voice of all in Qur’an recitation and he was from the taabi’een –the first generation after the Sahabah- meaning he met up with and knew some of the Sahabah. He died in the year 127 Al-Hijarah.
His two rawee are Shu’bah and Hafs.
He was Shu’bah bin Ayaash bin Saalim, and was called Abu Bakr. He was born in 95 Al-Hijarah and died in 193 Al-Hijarah. He was a great imam and working scholar, and was considered a reference of the great imams in the sunnah.
His name was Hafs bin Sulaymaan bin Al-Magheerah Al-Asadee Al-Kufee. He was born in the year 90 Al-Hijarah, and died in the year 180 Al-Hijarah. Hafs was the most knowledgeable of all in the recitation of ‘Aasim.
For the complete rules of Hafs ‘an Aasim, please see the following link: http://www.abouttajweed.com/tajweed-rules-for-hafs-an-aasim/index.php