Is it permissible to open a billiards club in a Muslim country without music, alcohol, or gambling, provided that payment is taken in advance? And will I be sinful if the players gamble outside the club? Is my income unlawful? And how can I ensure a lawful income from it?

If the billiard hall is free of prohibitions such as gambling, mixing of sexes, and neglecting duties, then there is no harm in opening it and earning a living from it. If the loser is forced to pay outside the hall, then the sin falls upon those who compelled him. It is recommended to advise the players about the prohibition of gambling and to display reminders of this in the hall.