Mt. Yoshizaki (commonly called Oyama in the locality), which is a small hill with a height of 33 meters above sea level and an area of 20,000 square meters, is a natural fort facing Lake Kitagata on three sides, namely north, west and south.
吉崎山（御山）とは、北･西･南の三方を北潟湖に囲まれた天然の要害で、海抜33m程、面積約2万平方メートルの小高い丘である。