Elaborating on what Vyre mentioned. Because of the semi-recent update to Save TP, ANY ws performed with a Tsurumaru will receive 25% TP return every time, regardless of your sTP. Additionally, your sTP on your TP set also changes, because you do not need to make up for TP lost on WS. In fact, you need to do the reverse. Your sTP should drop to allow you a little less than 19 TP per swing, 101% at 19TP/hit.
As an added bonus, Save TP caps at 50%, so when using the JA Hagakure, you will get 50% TP return instead of 40. If you have a really cool COR that will give you Miser's Roll, you will get 50% TP return on EVERY WS (on an 11 roll).
More than a year after this was introduced, it still stands as an amazing weapon. 25 TP return on weaponskill (35 under Ionis!), plus 15 accuracy for content like Yorcia Delve or D/VD SKCNM is incredible.
I don't know what the deal was when Delvish posted, but today it's super easy for SAM to get enough Store TP to get 25 TP per hit so you can Weapon Skill with this GK and then you just need 3 hits to get 100% TP again. Today that's what you should aim for rather than 4 hits at 19 TP each.
@Aleaseya That comment in response to the first brought me to tears xD. I thank you. But SE i think has gone mental. Only way E/M/R can compete now is if the update to them will boost them to 50-100 dmg more. Added to that you know the trials are gonna be like, collect 1500 Marrows or something stupid like that >.> With that being the case, Dynamis may no longer be full of perle BST