During the 1923 Great Kantō earthquake , widespread damage occurred in a region with a significant Korean population , and much of the local Japanese overreacted to rumors which spread after the earthquake . Within the aftermath of the event , there was a common perception amongst groups of far-right Japanese that ethnic Koreans were poisoning wells , eventually setting off a killing rampage against Koreans , where Japanese would use the shibboleth of '' ba bi bu be bo '' ( ばびぶべぼ ) to distinguish ethnic Koreans from Japanese , as it was assumed that Koreans would be unable to pronounce the line correctly , instead as . All people who failed the test were killed , which caused many ethnic Chinese , also unable to correctly pronounce the shibboleth , to be indiscriminately killed in large numbers . Other shibboleths used were and " '' gagigugego '' " ( がぎぐげご ) , where Japanese people pronounce initial '' g '' as and medial '' g '' as ( such a distinction is dying out in recent years ) , whereas Koreans pronounce the two sounds as and respectively
1923 Great Kantō earthquake
1923 Great Kantō earthquake
Anti-Korean sentiment