Sayyed Mohammad Al-Musawi, Sayyed Mohammad al-Musawi is originally from Iraq and heads up the World Ahlul Bayt Islamic League in London. Other than being involved in various humanitarian projects, he frequently responds to... Answer updated 1 year ago

http://www.duas.org/tahajjud.htm

Namaz Tahajjud can be performed either fully as 11 Rak'ats or shortly as three Rak'ats (2 Shaf' and one Witr) or in the shortest way which is just one Rak'at which is called Witr.

Wassalam.