What is the difference between katb Al-kitab and aqdun-nikah
Katb Al-kitab or marriage contract is an official promise to marry. It allows the couple to be together without a maharam, to touch and kiss. It is meant to be a transitional period, lasting between one month and one year.
Major differences to aqdun-nikah are:
- sexual intercourse is not allowed (as a consequence, it is an unwritten law that the couple has to organise aqdun-nikah immediately if the wife is pregnant!)
- it's not necessary that the couple lives together; katb Al-kitab is often chosen by couples who would like to live together but still have reasons to live in different places.
- separation from katb al-kitab must be declared but it doesn't need the full formalities of a divorce. There is no waiting period.
- dowry may be part of the contract but it needn't.
It's often chosen in my country because stately laws prescribe that stately marriage has to precede religious marriage, whereas katb al-kitab is allowed before stately marriage.
P.S. It's also allowed to make a civil contract together with nikah. This is a different subject.