The presence of the Ikki zealots was already straining Ōta's supplies of food and other resources even before the siege began. With the construction of a palisade and series of dikes roughly 300 meters from the castle, Hideyoshi began the process of isolating the castle from supplies, and flooding it, a process bolstered by heavy rains.
Before the siege, the Ikki zealots' presence was already causing Ōta's food and resource shortages. To cut off the castle's supply lines, Hideyoshi built a palisade and dikes about 300 meters away from the castle, then flooded it with the help of heavy rains.