checkered keelback

Notes:

This photo was taken in Bai-yun (White-cloud) Park, Guangzhou, China. I saw a wooden board on the tree-shaded grass somewhere in the park, and wondered what would be under. I moved the board with my foot and it revealed that there's a pit under, and suddenly something moved into the pit, making a noise like scraping the bush. At first I thought it would mostly be a rat or even a rabbit, but later it turned out to be a snake, slender figure, with length around 1 to 1.5 m if straighten up. I was afraid it's poisonous so I stayed a long distance (at least I think it's ok) from it and prepared to run at any second given it turned up onto me, so the photo may be not so clear. Is it poisonous? Well, whether so or not, safety is always the priority... The snake was obviously annoyed and a little bit agitated in my presence, it was fast-moving out and into the pit. At last, I moved the board onto the pit and made it covered again, I hope it would live undisturbed.