Lake Kuttara is a caldera lake in Shiraoi Town. It is the roundest lake in Japan. It is about 2.5km in diameter and its circumference is about 8km.
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Because the lake has no rivers flowing in or out, the water is crystal clear. It has a transparency of 19m.
![](https://akikotanigaki.com/wp/wp-content/uploads/2021/01/DSCN0027-1-t-600x450.jpg)
It is believed that kappa (water imps) live in Lake Kuttara. So there is a Yield sign on the road so that kappa can cross it safely.
![](https://akikotanigaki.com/wp/wp-content/uploads/2021/01/DSCN0030-600x450.jpg)