It was a round coin with a rectangle hole; the round shape of the coin had a diameter of 24.44 mm on an average, and had a square hole 6 mm on a side (to be exact, rectangle 0.5 mm longer on a long side) in the center.
平均の直径が24.44ミリメートルの円形で、中央には一辺が約6mmの正方形（厳密には、0.5mmほど横長の長方形）の穴が開いた、円形方孔の形式である。