I got one of these today just for ***** and giggles. Used it for like 4 hours and noticed that for Jins and Kus it wasn't as good as my fudos. Its no an extensive test by any means but I wouldnt get it unless you are gonna be busting out on hit ws's like ten all the time. If you have found otherwise then that cool, but from what I could see, not worth it.
The TP Bonus does work, I tested it against multipule types of mobs and the difference was noticeable in every case. With a 5-10 TP float I measured damage output at 100-110 TP with the same Weapon Skill and noticed minimum 40 Damag+ increase on WS and highest with Blade: Ten doing a difference of 80+Dam with the Shamo equipped v.s. unequipped with a stronger Dam base weapon such as Fudo.
The Shamo must be equipped in main hand (as previously mentioned) if you want the TP bonus to work. If you find yourself partying with Drk's and Sam's allot and working in skillchains, this Katana's TP Bonus comes in play nicely. Any bonus damage is good damage plus it allows you to do the same damage as High TP but in half the time waiting for TP.
I notice the post is old but ill give it a shot anyway.. Just "Follow the White Rabbit" :P other words its a bcnm/enm fight kill the rabbit nm and this can be one of the drops. I personally have not done this particular enm but with all the drops i see i doubt its a 100% drop but it could be.. Good Luck!!
For some reason, the developers choose not to follow their own name scheme. If they had, this would have been called the Martial Katana.
Like all the other Martial Weapons, any WS done with this weapon will perform as though the user had an additional 100% TP on top of what is shown in their TP Bar.
2 rules: You still need 100% TP in the bar to initiate a WS. If the user has 200% or more TP, the performance of the WS will be "capped" at 300%.