Pas Anfas - guarding every breath. A useful exercise to increase concentration and has lots of benefits. All/ most Akabir prescribe it. I have heard there are different ways of doing Pas Anfas:

1) Allahu
2) Yaa Hayy Yaa Qayyum
3) Laailaaha Illallah

Does anyone know the other methods of doing it and the benefits the Mashaikh say? Someone told me there are six