Colonel Hans Ritter von Seisser (German Seißer; 9 December 1874 – 14 April 1973) was the head of the Bavarian State Police in 1923.
In September 1923, following a period of turmoil and political violence, Prime Minister Eugen von Knilling declared martial law and appointed Gustav von Kahr, Staatskomissar (state commissioner), with dictatorial powers. Together with Seisser, and Reichswehr General Otto von Lossow, they formed a right-wing triumvirate in Bavaria.
That year, many right-wing groups wanted to emulate Mussolini's "March on Rome" by a "March on Berlin". Among these were the wartime General Erich Ludendorff and also the Nazi (NSDAP) group, led by Adolf Hitler. Hitler decided to try to seize power in what was later known as the "Hitler Putsch" or Beer Hall Putsch. Hitler and Ludendorff sought the support of the "triumvirate". However, Kahr, Seisser and Lossow had their own plan to install a nationalist dictatorship without Hitler.
Hitler was determined to act before the appeal of his agitation waned. So on November 8, 1923, Hitler and the SA stormed a public meeting of 3,000 people which had been organized by Kahr in the Bürgerbräukeller, a large beer hall in Munich. Hitler interrupted Kahr's speech and announced that the national revolution had begun, declaring the formation of a new government with Ludendorff. While waving his gun around, Hitler demanded the support of Kahr, Seisser and Lossow. Hitler's forces initially succeeded at occupying the local Reichswehr and police headquarters; however, neither the army nor the state police joined forces with Hitler. Kahr, Seisser and Lossow were briefly detained but then released. The men quickly withdrew their support and fled to join the opposition to Hitler.
The following day, Hitler and his followers marched from the beer hall to the Bavarian War Ministry to overthrow the Bavarian government on their "March on Berlin", but the police dispersed them.Sixteen NSDAP members and four police officers were killed in the failed coup.