It is a two level style round burial mound, 23m diameter (lower level), 18m (higher).

It took me about two and a half hours to dig a hole one meter in diameter and two meters in depth.

What is the distance across the pond?

The lake is three miles across.

The pond is 100 meters in diameter.

The lake is four miles across.

The hole is two meters across.

The hole is about five feet across.

The diameter of the hole was slightly larger.

Is it possible to determine the diameter from the circumference?

This evening, until 8pm, there will be a partial lunar eclipse over a large area of Japan. Since 98% of the Moon's diameter will be hidden, it will seem almost like a total lunar eclipse. This is the first deep partial eclipse in Japan in 140 years. Don't miss it!