This is an interesting and common snake that I often see in Hong Kong, as it is active both during the night and day, and it is of course the Checkered Keelback.
This one popped up in a pond hunting frogs.
For more information about this snake, or any other HK snake, see our sister website www.hongkongsnakeid.com and the FIELD GUIDE TO THE SNAKES OF HONG KONG.