The gurdwara at the birthplace of Guru Nanak Dev Ji was held by a mahant, Narain Das, of the Udasi custodial line, whose conduct and management of the shrine's large revenues had become a scandal.
On 20 February 1921 a jatha of about 150 Akali reformers under Bhai Lachhman Singh Dharowali entered the shrine. The mahant had hired armed men and had prepared. The gates were shut. The jatha was shot and cut down and the bodies were burned inside the compound. Estimates of the dead run from 86 to over 150.
Bhai Lachhman Singh was tied to a tree and burned. Bhai Dalip Singh, who had come to negotiate, was killed.
The massacre turned the Gurdwara Reform Movement from a series of local disputes into a mass campaign. The SGPC and the Shiromani Akali Dal already existed, both formed in late 1920, and the massacre gave the SGPC its authority. It led directly to the Sikh Gurdwaras Act of 1925, which transferred the historic shrines to elected management.
The site is in Pakistan. Sikh pilgrims visit on gurpurab under a visa arrangement, and the graves of the 1921 dead are inside the complex.
In February 1921 a jatha of about a hundred and fifty went to Nankana Sahib to take possession of the shrine from its mahant, and they were fired on and killed inside the complex.
The bodies were burned. The number is generally given as around a hundred and thirty and it is not exact.
It is the single most violent episode of the Gurdwara Reform Movement and it turned the campaign into a mass movement. The site is in Pakistan.