There was a huge influx of homeless people into Edo and its environs due to the Great Tenmei Famine and the resulting political instability, and many of the homeless committed a wide variety of serious crimes.
天明の大飢饉など、折からの政情不安により発生した無宿が大量に江戸周辺に流入し、様々な凶悪犯罪を犯すようになった。