In turbulent Shanghai in the years between the world wars the International Settlement was a mercantile powerhouse that faced unrest from Communist labour unions criminal gangs spies political agitators armed kidnappers & assassins. Adjoining the Settlement were the French Concession & the Chinese city both hotbeds of intrigue & crime themselves. Called the most sinful in the world the Settlement relied on its police: the Shanghai Municipal Police one of the most advanced forces in the world. After an incident in 1926 when the police fired upon demonstrators which resulted in unrest & strikes W. E. Fairbairn was charged with forming a specialised unit to deal with riots & armed encounters. The resulting Reserve Unit became the prototype for future SWAT teams as it developed tactics for using snipers in barricade & hostage incidents techniques for use of the sub-machine gun during raids hostage rescue tactics aggressive riot-dispersal tactics & various other tactical innovations. Out of the experiences of the unit came many of the techniques later taught by W. E. Fairbairn E. A. Sykes Pat ONeill & others to the Commandos Rangers SOE OSS 1st Special Service Force & other Second World War elite units. Those same techniques still resonate today with special forces & police tactical units.