A Code of Practice For Muslims in the West : Youth's issues » General Rules
Fatawa of Ayatullah al Uzama Syed Ali al-Husaini Seestani
503: It is harãm to play chess, regardless of whether or not the play is with betting. It is also harãm to play chess through computerized instrument, if there are two players involved in it. Based on obligatory precaution, one must refrain from it, even if just the computer is the other player.
504: It is similarly harãm to play with instruments of gambling in which betting is involved. Based on obligatory precaution, one must refrain from it even when no betting is involved.
522. Question: Is it permissible to play games of chance of all kinds on electronic machines (computers) without betting or with betting?
Answer: It is not permissible, and it is treated the same as normal [non-electronic] gambling instruments.