I was curious about which Bicheon Mastery skills everyone thinks are either incredibly useful or incredible useless.
I've read enough on the forum to see that there's a general consensus Chain Sword Attack, Hidden Blade, and Killing Heaven Blade are "must-haves" for anyone choosing Bicheon. (and I 'think' the passive also)
I've tried Castle Shield in the Shield Technique series and because you can't attack while using it, it's a waste of SP. I've also tried Soul Cut Blade in the Blade Force Series and that seems like a waste of SP also.
The only skill I haven't been able to test for myself is the Sword Dance series so I'm not sure how useful that is. There's a blade guide on this forum that gives a description of the skill but I still don't really know if it's worth spending the SP on.
Here's the Blade guide with descriptions of all skills.
http://www.silkroadforums.com/viewtopic.php?t=4676
Here's the link to my favorite Blade guide. (Fly's SRO guide to the 3 most powerful builds)
http://www.silkroadforums.com/viewtopic.php?t=1575
Use this SRO Skill Calculator to see all the skills if you need to.
http://sro.mmosite.com/x/