Shiroyama Park is the former site of Sannohe Castle, built in the Warring States Period (15th to 16th century). Visitors to the 28-hectare park today can enjoy recreated castle buildings as well as around 1,600 somei yoshino, double-blossomed yaezakura, weeping shidarezakura, and yellow ukon. The Sannohe Spring Festival is held from late April to early May, with singing and dancing events each day.