Sanada Maru (真田丸) was a fortification attached to Osaka Castle. It is playing a key role in defending the castle……Sanda Yukimura, no.1 Japan warrier, build this in front of the outer moat, at the Kuruwa port and southeastern Hirano-guchi (平野口) gate and beside the Kuromon-guchi (黒門口)…… It became a main obstacle to the main Tokugawa force….. The place where Sanada Maru was located is north of the little hill, Sanadayama Park. Osaka castle, represented the last obstacle to Japan’s unification. Toyotomi Hideyori appointed Sanada Yukimura as a commander to opposing other army who were trying to get in …….The castle had two moats, which created an outer moat between the canal that existed to the west and the Nekoma stream which flowed from south to north on the eastern side. This often referred as the last stand of the Samurai……very hard to attack and get in…..