This is of course the BAMBOO VIPER Trimeresurus albolabris, or also called the white-lipped viper.
Make sure you check out more information about this and other snakes over at: www.hongkongsnakeid.com and at
Active at night and occasionally roosting in bushes during the day. The Bamboo Viper is an ambush predator that will wait in a single position ready to strike. They are a viper and have relatively long retractable fangs and will bite readily at anything that comes within range. A bite from a Bamboo Viper should be considered very serious and medical attention should be sought immediately. Although not known to be deadly serious damage can occur from a bite even if treated and complications can always arise.
but how about this one, a close relative, that I found on Komodo Island, in Indonesia a few years back....Called the white-lipped island pit viper (Trimeresurus insularis)
Yep, its blue....but also had a red streak on its tail.