Why is this important to keep secret? We're supposed to be stepping down our conflict with the Hag anyway. And he doesn't have any proof that we burned his shack down, just suspicion.
If the Goketsu get wrongfully accused of every minor misfortune (including another clan's misdeeds) because of our ability to put seals on black paper, then we laugh at them, point out how busy we are with the Dragonwar, learning the Bijuu Seal, Clan Head paperwork, and learning all the seals that Asuma orders us to learn.
If the false accusations keep happening, we go to Asuma about them distracting from our progree on Dragons.
If they keep happening after that, we actually start doing the things they've accused us of doing.
For the same reasons giving up secret in ninja world is a really bad idea:
-It reveals we can use Black Seals with all his specific issues (Hagoromo, people will want to capture and obtain Hazou, it lets people prepare countermeasures against this particular secret, it generally means we cannot use it anywhere without being a Goketsu calling card, a bunch of other problems i can't find out at the top of my head).
-It also gives our enemies(and allies, that could even be worse in some cases) information on how we could have created them, remember Shino going "Hazou probably used Earth Ninjutsu to make lenses"? People are smart and can make inferences on how we create things.
Generally in ninja world, the rule is "Do not give away secrets if you can help it" and it follows this rule for a reason, any OPSEC leak could be nothing or could be absolutely catastrophic, and the smart idea is to...not have OPSEC Leaks.
...I see a few things wrong with this.
- Seals are a one time use, reliant on a continuous supply. Jutsu can be taught to anyone after they've been learned. The original tutor has no control over what their students do with the jutsu.
- Even if we give her the research notes, it wouldn't be a TN60 attack. The resultant seal would have a TN based on the Yamanaka Sealmaster's sealing level. The whole reason Ino wants Goo Bombs is for her genin to have a TN60 attack available to them.
- Goo Bombs aren't as great as a what you're asking for.
- Mari said that doing such a thing would be asking for a jutsu that inherently makes Yamanaka jutsu less effective on thr caster.
- Not only would trading away a Resolve Boosting jutsu empower Hazou, it would also weaken the Yamanaka Clan because it would make their jutsu less effective on him.
- It also opens up the threat of propagation. What if Hazou teaches the jutsu to Team Uplift? Or the wider Goketsu Ninja? What if he sells it to another clan, or makes it public domain? The Yamanaka Clan would be horrifically weakened, permanently.
This is why i said "This is just the jumping point to propose a better deal".
We could ask for the jutsu to only be teached to Hazou in exchange for a lifetime supply of Goo Bombs + Hazou personally teaching X amount of seals to their sealmasters, or a Clan secret sharing contract, or Orochimaru's notes or a bunch of other stuff.
Personally i feel that giving it away for free without even trying to obtain the one thing we really want to be a waste: we have a bunch of stuff that ninjas would kill for, a EJounin social spec, Kei and a girlfriend willing to work with us, i feel we should try to obtain something more than "give away one of the most important secrets the clan has for some off-screen stuff that will have absolutely no impact in the narrative or mechanics of the story".
I'm stressing this because we don't have a deadline at the moment, we're deciding to vote on it, so we can refine the plan as much as we want, after all.
