The dhikr begins with slow beating of a drum and tambourines. A leader starts chanting a phrase like 'God lives' over and over again. The Sufis - colloquially, they call themselves dervishes - stand in a big circle, chanting in time to the drum, throwing themselves forwards in a deep bow and then backwards. Many of them let their hair grow and it flails around their heads as they bow and bend.
The Shaikh stands in the centre of the circle, swaying gently and sometimes closing his eyes and opening his hands in prayer. The drums and tambourines go faster and faster, the chanting gets louder and louder, and the dervishes go into a trance.
I went to a dhikr once before, more than 20 years ago in the Syrian desert. I nearly passed out. There were a couple of dozen men crammed in a small room and the drumbeat and chanting was so loud it seemed to take over my heartbeat. I managed to watch a local policeman drive a skewer through his belly but I admit I closed my eyes when the leader of the dhikr laid a young novice face down on the floor, put a knive across the back of his neck and knelt on it.
Today's dhikr was less emotionally overwhelming but in a way more amazing because I didn't pass out and the men sticking knives into themselves didn't seem to be in a real trance. The razor blade eater gave me a razor blade to feel before he started eating it, and the man who hammered daggers into his skull took instructions from his colleagues on which way to look for the camera.
But they were in the presence of the Shaikh of the whole Qadiri Kasnazani Order. Before the dhikr, they queued up in hundreds - maybe three or more thousand - to kiss his foot. Today was one of the biggest events in the Muslim calendar, the Feast of Sacrifice, and groups of dervishes had come from all over Iraq to greet the Shaikh. The most important guest was the Shaikh's deputy in Russia, a Chechen called Adam-Shamalu Deniyev who is developing his own religious theory of 'Adamallah-Humanity'