Oyachi

Japanese: 大谷地 - おおやち

…It is located at the northeastern edge of the Yonezawa Basin. The northern part belongs to the Shirataka Hills, and the southern part is the alluvial plain of the Mogami River that continues into the dissected alluvial fan of the Yoshino River. In the eastern part, there is a peat marsh called Oyachi, which honors Lake Hakuryu. There are remains of Jomon and Yayoi periods, as well as ancient tombs such as the Inarimori Tomb. …

From the Yonezawa Basin

…The alluvial fans formed by these rivers have developed around the periphery of the basin, and the Matsukawa River, which is the upper reaches of the Mogami River, flows north through the center. In the northeastern part of the basin, there is a peat marsh called Oyachi, and Lake Shiraryu, located in the center, is said to be a remnant of the former lake basin. Currently, land improvement work is underway in Oyachi, and it is being converted into dry rice paddy fields. …

*Some of the terminology that refers to "Oyachi" is listed below.

Source | Heibonsha World Encyclopedia 2nd Edition | Information

Japanese:

…米沢盆地の北東端に位置する。北部は白鷹丘陵に属し，南部は吉野川の開析扇状地に続く最上川の沖積地が広がり，その東部に白竜湖をたたえる大谷地（おおやち）といわれる泥炭湿地帯がある。縄文･弥生時代の遺跡や，稲荷森古墳(史)などの古墳が残されている。…