The center and centerpiece of Motsuji's temple garden is the seasonal beauty of Oizumi ga Ike. This pond measures 180m east-west by 90 north-south, and is unchanged since the garden was created in the twelfth century.
An arc-shaped island roughly 70m by 30m dominates the middle of the lake. Naturally round stones cover both it and the perimeter of the pond.
In the past, bridges connected the island to the shores. On the gate side was a 17-bay arched bridge, on the Hondo (Main Hall) side a 10-bay skewed bridge. The bridge-anchoring stones from the four corners of both bridges, and the bridge piers of the arched bridge have been unearthed. Two of the piers, each about 27cm in diameter, are on display in the Cultural Assets Repository. These are Japan's oldest bridge remains.