The 1918 influenza pandemic, commonly known as the Spanish flu, was the worst demographic disaster resulting from a single cause in the 20th century. This influenza lasted from the spring of 1918 toward the end of the First World War to the spring of 1919, and spread widely around the world, resulting in at least 20 million deaths, by some estimates up to over 100 million deaths. Epidemiologically, there were three waves during this period. It was around September 1918, which was the second wave period, when the 1918 influenza pandemic first became known in colonial Korea. It is estimated that influenza was imported to the northern region of the Korean peninsula on the South Manchurian Railway.
According to official results announced by the Japanese Government- General of Korea in March 1919, 7,556,693 out of the estimated total population of colonial Korea of 17,057,032 suffered from the influenza pandemic, with 140,527 deaths recorded (at a mortality rate of 0.82%).
However, it is likely that the total number of those who contracted the disease and the number of deaths were both greater than the official figures.
In 1918, the Japanese Government-General of Korea’s preventive measures against epidemics was based on the military force of the military police centering on the National Police Agency. However, being such a long time for the cause of influenza to be clarified at the time, influenza fell outside the scope of legal regulations and there were no effective preventive measures. The National Police Agency was busy counting the numbers of patients and deaths through house inspections carried out by the military police, and they were unable to handle the influenza pandemic effectively. Korean people witnessed deaths every day due to the incompetence of the Japanese Government-General of Korea, which failed to prevent influenza, and the peninsula had reached the point where people felt the capacity to express a despair that had accumulated over 10 years under military colonial rule.