In the latest chapter we have learned that Zoro has taught Momonosuke a unusual word to shout when training his sword skill and that word is “snatch”.
Momonosuke is immediately told not to use that word because in the old Kuri Dialect there was a yell like that as well and it is not befitting of someone with Momosuke’s status. In the panel you will notice they show Zoro in a scary pose and there is sweat coming down O-Kiku’s face as she warns Momosuke not to use that word implying that she is really downplaying how big of deal it really is for him to use that word
The other thing we can take away from this is that she says “it may just be coincidence” but from a writing stand point you are just not going to say this unless it is most certainly NOT a coincidence, this is foreshadowing.
Kiku’s reaction to “snatch” made me think of word taboos in ancient China or Japan. People would avoid words that were associated with negative things or bad luck (and some of these superstitions are still present today, for example avoiding the number 4 because it sounds like “death”).
From there I came up with a theory:
Maybe the “snatch” yell is related to an ancient samurai clan that inhabited Kuri a long time ago – definitely before Kiku’s time 20 years ago. It could have been that clan’s trademark shout or battle cry, being described as “a way to strengthen your heart when your courage falters”.
The clan later became infamous/was exterminated for whatever reason, and everything connected to it, including their distinctive yell, became taboo for the people of Wano, who started to avoid anything related to them out of fear of bad luck or repercussions. So “snatch” became a forbidden word.
What if the survivors of that clan, exiled or fleeing from Wano, ended up in the East Blue and are Koshiro’s ancestors?
That would explain why Koshiro, a dōjo master in a remote village in the weakest sea, had one of the 21 Ō Wazamono swords.
Zoro must have learned that yell and the meaning associated to it from the person who trained him– Koshiro. Zoro himself can’t be from Wano because Oda repeatedly stated he was born in the East Blue, but we know nothing of Koshiro’s family origins.
This would give Koshiro and Kuina a Wano ancestry, and give Zoro a further connection to Wano through them and Wadō Ichimonji.
Also, the person (or people) Hitetsu has been waiting for in Kuri could be someone from this clan who had vowed to go back to their homeland one day.