The Sieges of Nagashima (長島一向一揆, Nagashima Ikkō-ikki), taking place in 1571, 1573, and 1574, were part of Oda Nobunaga's campaigns against the Ikkō-ikki, arguably among his greatest enemies. Nagashima, in Owari Province along Japan's Pacific coast, was the location of a string of river island fortresses and defensive works controlled by the Ikkō-ikki, which surrounded their Ganshō-ji monastery. This string of defenses included Nagashima Castle, which they had captured previously. Oda Nobunaga attacked three times over the course of four years, before finally destroying the entire Nagashima complex. These sieges were executed concurrently with Nobunaga's eleven-year siege against the Ikki's primary fortress of Ishiyama Hongan-ji.