Al-Kāfi - The Book of Drinks

15.A number of our people have narrated from Sahl ibn Ziyad from ibn Mahbub from ibn Ri’ab who has said the following: “I once visited abu ‘ Abd Allah (a.s.), and said, ‘I pray to Allah to keep my soul in service for your cause, what do you say about chess?’ He (the Imam) said, ‘One who turns it from side to side is like one who turns pork from side to side.’ I then asked, ‘What must one who has turned pork from side to side do?’ He (the Imam) said, ‘He must wash his hands.’” شهور - Allamah Baqir al-Majlisi (Mirʾāt al-ʿUqūl fī Sharḥ Akhbār Āl al-Rasūl (2/310))