Original: According to Kojiki , the entrance to Yomi lies in Izumo province and was sealed off by Izanagi-no-Mikoto upon his flight from Yomi , at which time he permanently blocked the entrance by placing a massive boulder ( Chibiki-no-Iwa ) at the base of the slope that leads to Yomi ( Yomotsu Hirasaka ) .
Simplified: The entrance to Yomi was blocked by Izanagi when he returned to Earth , using a great boulder ( Chibiki-no-Iwa ) at the base of the slope that leads to Yomi ( Yomotsu Hirasaka ) .