The Legend of Tatsuko
Many centuries ago Lake Tazawa was known as Tazawa-kata, or Tazawa Lagoon. The legend goes that in the nearby town of Innai there used to live a young woman of unsurpassed beauty named Tatsuko. One day while fetching water in Ainaigata at the north end of the lagoon, Tatsuko happened to catch sight of her reflection in Kagami-ishi, a mysterious rock (ishi) that shone like a mirror (kagami).
Seeing her own beauty, and understanding that it was fleeting, she desperately wished to preserve it for eternity, and prayed for countless nights to Okura Kannon, the goddess of mercy and compassion.
Finally, she received an answer: “If you drink the water that gushes forth from the spring to the north, your wish will be granted.”
Telling her family that she was going to gather wild greens, Tatsuko slipped away into the wilderness, and eventually came across the spring, now called Katagashira-no-reisen, the “Miraculous Spring of Katagashira,” flowing from between two moss-covered boulders. Overjoyed, Tatsuko cupped her hands and drank deeply. The more she drank, however, the thirstier she became, until at last, lying stretched out on her stomach, she drank the spring dry.
Then to her horror, Tatsuko realized that she had transformed into a dragon and threw herself into Lake Tazawa. She had become—and remains still—the dragon guardian of the lake: Tatsuko-hime-no-kami.
Tatsuko’s mother, worried by her absence, went in search of her daughter, and was distraught by what she found. In her grief, she hurled what remained of her wooden torch into the lake, where it became the first kunimasu, or black kokanee, a rare species of landlocked salmon that was once native to Lake Tazawa.
The dragon Tatsuko-hime-no-kami is not alone, however. Legend has it that her lover, Hachirotaro of Hachirogata Lagoon in the Oga Peninsula, visits her every fall, staying through the winter. Its resident dragon absent, Hachirogata Lagoon freezes over, but Lake Tazawa, with two dragons swimming in its depths, remains free of ice throughout the winter.