The Silk Letter Movement (تحریکِ ریشمی رومال) refers to a movement organised by the Deobandi leaders between 1913 and 1920, aimed at freeing India from the British rule by allying with Ottoman Turkey, Imperial Germany, and Afghanistan. The plot was uncovered by Punjab CID with the capture of letters from Ubaidullah Sindhi, one of the Deobandi leaders then in Afghanistan, to Mahmud al Hasan, another leader then in Persia. The letters were written in silk cloth, hence the name.
Muhammad Mian Mansoor Ansari went to Hejaz with Mahmood Hasan in September 1915. He returned to India in April 1916 with Ghalib Nama (Silk Letter) which he showed to freedom fighters in India and the autonomous area and then took it to Kabul where he reached in June 1916.
With the onset of World War I, Ubaidullah Sindhi and Mehmud Hasan (principal of the Darul Uloom Deoband) had proceeded to Kabul in October 1915 with plans to initiate a Muslim insurrection in the tribal belt of India. For this purpose, Ubaid'Allah was to propose that the Amir of Afghanistan declares war against Britain while Mahmud al Hasan sought German and Turkish help. Hasan proceeded to Hijaz. Ubaid Allah, in the meantime, was able to establish friendly relations with Amir. As the plans unfolded in what came to be called the Silk Letter movement, Ubaid'Allah was able to establish friendly relations with Amir. At Kabul, Ubaid'Allah, along with some students who had preceded him to make way to Turkey to join the Caliph's "Jihad" against Britain, decided that the pan-Islamic cause was to be best served by focussing on the Indian Freedom Movement.