Final Kawanami Clan Armor smithing text results:
~250 Koroku kills in The Shiftling's Wise Judgment and nothing.
3 Koroku kills in The High-Spirited Demon (THsD) and it drops.
I wasn't even farming for it in THsD, I just wanted to get the individual pieces for refashioning. The desire sensor is real.
At this point it is also safe to say it couldn't actually drop in the first mission, contrary to what the fanmade spreadsheet says.
In the meantime I have also mastered the Sword, Tonfas and Odachi. I initially discarded the sword because I thought it was offensively vanilla, but it's actually a surprisingly fun weapon. The sheathing animation when there's blood on the weapon might be the slickest of the bunch.
The fights against the odachi weapon master in particular highlighted a real problem I have with the game and its "your rules aren't my rules" nonsense. When I do a combo and the first attack misses, and I still choose to follow up with a second attack, I remain locked into the direction I was initially facing and I'm basically wide open until the animations runs out. This happens quite often with the tonfas' Demon Dance > Pulverize combo. And I mean, it's fine since continuing the combo was a mistake on my part. Yet when the AI misses its first attack, it simply adjusts automatically for the second attack to go in your direction. The odachi weapon master did it with some of his combos and Maeda did this too with one of his rapid spear thrust combos.
You can argue that the AI is at least consistent in their combos, and eventually you will recognize these combos and know when to continue dodging/blocking. But it is easy to misread a move in the heat of the action and it sucks to get punished with a stunt you could never hope to pull off, especially when you feel like you were actually doing OK.
Somewhat related is the inability to hit bosses in particular out of certain attacks. Sometimes it feels it should happen, especially in case of particularly hefty attacks, but then the boss just eats the hit, laughs and kills you for trying. The game is very aggressive in enforcing its "wait for your turn" philosophy, where I wish it would instead reward the player for taking these kind of risks.
Lastly, I am currently playing through Mausoleum of Evil and it just baffles me how I die over and over to that first Ubume. I fought them enough times by now to predict their behavior, or so I thought. But I am starting to think the game intentionally adjusts enemy behavior depending on the level. There has to be a reason why she almost never does her burst grab attack normally, yet spams it in this encounter.
Oh, and sorry for another rambling post. But this is the stuff that keeps me awake at night.