Mukashi Shinden (昔神殿, Japanese for Temple of the Ancients) is a small island located off the western coast of Soul Society that can only be reached using a boat across the spiritual seas from the Rukongai or via Senkaimon, though the latter is rare as few even recall the existence of the island in the first place due to its secrecy. Before the massacre, the Yuengiri used the island as a spiritual retreat, and to this day the temple complex they created still holds some of their greatest treasures, secrets and achievements. The island have had strong links with the Shiba Family since its founding.