This monument represents the remains of Komachi Izumi (Komachi Pond) near Isozaki Shrine.
It is known as Komachi Izumi or Komachi Sugatami no Ike, as it is said that Komachi used to look at the pond to see her reflection. Fukakusa no Shosho, who came all the way from Kyoto to Dewa just to see Komachi, confessed his feelings to her and started Momoyo Gayoi (100-day straight visits).
At the time, Komachi was suffering from smallpox, and she could not meet Fukakusa. She visited Isozaki Shrine every day to wash her face with clean fresh water from Komachi Izumi, praying that she would be cured as soon as possible.