No he didn't. Jack
knew Raizou was on Zou. He didn't just have a hunch.
Jack didn't
just want to torture the minks. He wanted to have Raizou. He didn't just beat up Sheepshead over a hunch. He
knew for a fact that Raizou was on Zou somewhere. Hence why he went through the effort of having to return and not simply letting the minks die from their previous attack.
Kanjuro cannot be the traitor since Kanjuro himself didn't know for sure that Raizou had even made it to Zou.
Have I simply misremembered or are you making stuff up? When did Kin emon, Raizou and Kanjuro split a vivre card? If they had vivre cards of each other, then there wouldn't have needed to be such a big search for Kanjuro on Dressrosa, nor would they have had to ask where Raizou was when they arrived on the back of Zou.
So taking your stance, some days before the events of Dressrosa, Kanjuro managed to inform Kaido and Orochi that Raizou was on Zou, (despite having no confirmation of this), and whilst contacting Kaido and Orochi, he refused to mention anything about the kozuki ankle symbol (despite having full knowledge of its meaning), and hence was selective in the information he gave?
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Reading your first post again, there's more that either doesn't add up or is simply wrong.
No one wondered why their ship was sabotaged, because it wasn't sabotaged...
It was clearly stated that they cashed because of their inexperience. Not because Kanjuro secretly sabotaged their ship.
Your post completely skips over everything we know about Kanjuro's character. Not to mention, we know that he is part of the prophecy.
So the prophecy was wrong, and there were actually only 8 samurai that will emerge to kill Orochi? Prophecies can be vague and mysterious, but you'd think that they'd at least get the number correct.