The space after the courtyards which leads to the avenues around the holy shrine is called as Bast. The Basts situated after the courtyards are the frontal limits for safeguarding the buildings of the holy shrine. It is also the shelter house for the pilgrims during any occurrence of any accident. It is also the place where the pilgrims get ready to visit the holy shrine and thus the places for ablution (wuzukhaneh) are also situated in these Basts. Four Basts are located in four different directions of the holy shrine and are named after four renowned and distinguished Shi'ite scholars.
1. Bast Shaykh Toosi (Upper Bast):
This Bast is situated on the west of the Inqilab courtyard and is 86 meters long and 30 meters wide. Eastern part of this Bast is connected to Sahn Inqilab and the western part leads to Shirazi Avenue. The entrance of the Central Library of the Astan Quds Razavi has been located in this sanctuary. The west side of the sanctuary leads to Shohada (martyrs) Square.
2. Bast Shaykh Tabarsi:
This Bast is located in the north of Inqilab courtyard between the buildings of the Central Library and the Razavi University of Islamic Sciences. It is connected from south to the Inqilab courtyard and from north to the Tabarsi Avenue. Its length is 86.50 meters and its width is 24 meters.
3. Bast Shaykh Hur Ameli (Lower Bast):
It is located on the south-eastern side of the Holy Shrine. From west it is connected to the Inqilab Courtyard and from east to Nawab Safavi Avenue (Payeen Khiyaban) and is 115 meters long and 29 meters wide. On the northern side of the Bast, the Astan Quds Razavi Inn(Mihman Sara) and the entrance to Razavi University of Islamic Sciences are located. On its southern side the telecommunication office, entrances to the Azadi courtyard and Imam Rida (A.S.) Hospital are situated.
4. Bast Shaykh Baha'i:
This Bast is located on the south-western side of the holy shrine and south of Dar -al-vilayah porch. From north of the Bast, there is the entrance of Dar -al-Vilayah porch, passages to the Do- Dar, Parizad and Balasar Madrasahs (Islamic Seminaries), Jumhuri Islami courtyard and Gowharshad Mosque. The rest house for the servants of the holy shrine and the illumination department of the holy shrine are located in this place. The southern side of the Bast leads to the Sahn Jameh Razavi.