The Sieges of Nagashima took place in 1571, 1573 and 1574 in Japan. Nagashima was a fortress controlled by the Ikko-ikki. Actually, it was a whole series of fortresses and defensive works. Oda Nobunaga attacked three times over the course of four years, before finally destroying Nagashima itself.

1571

Nobunaga's forces attacked across a river. Unfortunately, the samurai's horses got stuck in the mud. The samurai that managed to drag themselves to shore — while being fired on — were drowned when the defenders opened a dike and flooded the area. It was a total disaster for Nobunaga.

1573

Nobunaga's run of ill-luck with the Ikko-ikki continued when a rainstorm hit just as he was about to open the battle with his arquebuses. The rain rendered them useless and left his men in a weak defensive position. The Ikko-ikki troops immediately counter-attacked. Their arquebuses were covered during the storm and they started using them as soon as the rain let up. The Ikko-ikki troops came close to killing Nobunaga. He retreated.

1574

Fate was kinder to Oda Nobunaga on his third attempt to reduce the fortress at Nagashima.

While a fleet of ships lead by Kuki Yoshitaka blockaded and bombarded the area, Oda took the outer forts. Eventually, the defenders were forced back, into the castles of Ganshoji and Nagashima. There were about 20,000 of them and they were now completely cut off. As their situation worsened, it became more and more pointless for Oda's enemies to try to help them, and the defenders found themselves without anyone willing to try to help them.

Oda's men built a wooden wall from one outer fort to another, cutting the Ikko-ikki off from the outside and preventing them from seeing what was coming. Nobunaga had wood piled against the wall and lit of fire. The fire spread to Ganshoji and Nagashima. All 20,000 of the defenders were killed.

The article incorporates text from OpenHistory.