When the castle fell, most members of the Araki family were killed, but Matabe, who was in his second year, was saved by his nanny and sheltered in Ishiyama Hongan-ji Temple, and then came to use his mother's family name, IWASA, as his family name.
落城に際して荒木一族はそのほとんどが斬殺されるが、数え年2歳の又兵衛は乳母に救い出され、石山本願寺に保護されて、母方の「岩佐」姓を名乗るようになる。