In Tōhoku, which is the north-eastern region of Honshū, starting in the 1770s there was a sharp decline in crop yield due to poor and cold weather, so food stocks in rural areas were exhausted. The situation was exacerbated by natural disasters: Mount Iwaki erupted on April 13, 1783 (March 12, Tenmei 3 in the Lunisolar calendar), as did Mount Asama on July 6 (August 3 in the Lunisolar calendar), so volcanic ash was sent down into the atmosphere of Japan. Aside from the direct damage caused by the eruptions, this led to a fall in solar radiation, resulting in cold weather that catastrophically damaged crops. The massive Icelandic Laki eruption of 1783 which disrupted weather patterns all over the Northern Hemisphere undoubtedly worsened matters as well.