Bleachas a series isn’t generally known for its foreshadowing, but looking back at key scenes with the information fans have now, there were actually some extremely clever hints at Ichigo’s secret heritage. One such scene occurs during the Soul Society arc, hundreds of episodes before his heritage would be revealed.
InBleach: Thousand-Year Blood War, it’s revealed thatIchigo’s mother, Masaki Kurosaki, was a Quincy, making Ichigo part-Quincy as well. This is first demonstrated with Ichigo subconsciously using a technique known as Blut Vene while battling Yhwach for the first time. The Blut Vene technique is a Quincy ability which allows them to control the flow of their blood for defensive applications, and many of the Stern Ritter are seen using it throughoutThousand-Year Blood War. Once Ichigo learns the truth of his heritage, he gains some control over the ability, but it turns out he actually used it for the first time long before.

Bleach Hinted at Ichigo’s Quincy Heritage Way Back
The Soul Society Arc Teased Ichigo’s Quincy Ability Early
During the Soul Society arc, where Ichigo and friends invade to save Rukia from execution, Ichigo comes across the monstrously powerfulSoul Reaper Captain Zaraki, who engages him in battle. As Ichigo struggles against this powerful foe, the spirit of his Zanpakuto, Zangetsu, comes to him, and explains that he has been stemming the flow of Ichigo’s bleeding in order to help him stay in the fight longer, but he’s approaching his limit. Ichigo acknowledges this and prepares to end the fight quickly, but Zaraki doesn’t make it easy for him.
No other Soul Reaper has ever shown the ability to control the flow of their blood. While the Blut Vene technique had not yet been used in the anime, since Uryu was the only Quincy and wasn’t aware of the technique,there’s no doubt that this is the ability that Zangetsu is using to help Ichigo here. Furthermore, it’s revealed inThousand-Year Blood Warthat Zangetsu is not actually the manifestation of Ichigo’s Zanpakuto; instead, he’s the manifestation of Ichigo’s Quincy powers, and the “inner Hollow” White Ichigo is actually the spirit of his Zanpakuto. It makes complete sense that “Zangetsu” would have this power.

Bleach Teased Zangetsu’s Truth in Other Ways
Ichigo’s “Old Man” Was Hinted to Be More Than He Let On
Ichigo often called “Zangetsu” the “Old Man,“rather than by his name. However, the “Old Man” never actually told Ichigo his name was Zangetsu; when the “Old Man” tells Ichigo his name in the anime, it is concealed with static, while in the manga, the name is blotted out with black ink.This strongly suggests that Kubo already knew that the “Old Man” wasn’t actually Zangetsu at this stage of the writing, and that he had a very different role to play in the story than that of a Zanpakuto spirit. While many fans will swear the “Old Man” says his name is Yhwach, in truth there’s no distinguishable name stated at all.
Fans also like to point out that Ichigo’s bedsheet in episode 3 of the anime features a five-pointed Quincy Cross, perhaps suggesting that Ichigo’s Quincy heritage was planned from the very beginning. It’s worth noting, though, that the Quincy Cross has been through a few variations; the version initially used by Uryu was four-pointed, and resembled a Celtic Cross, while the five-pointed cross only appeared later.

Was Ichigo’s Heritage Already Decided?
The Foreshadowing May Be Convenient Retcons
It does seem unlikely that Kubo would have already developed the Quincy’s Blut Vene technique hundreds of chapters before it became relevant, so it’s possible that this was merely a coincidence that fits well with Ichigo’s altered heritage. However, there is no other explanation for what the “Old Man” is using. It’s clear that the “Old Man” was always meant to be something distinct from Zangetsu, soperhaps when Kubo was developing Yhwach and his Stern Ritter, he looked at some of the abilities that the “Old Man” had demonstrated, andretroactively made them into Quincy techniques.
Whether Ichigo was intended to be a Quincy from the beginning or not, this scene certainly makes for an interesting moment during a rewatch of the series, and hits very differently for those who are aware of Ichigo’s status as part-Quincy. The “Old Man” even uses a technique similar to the shadow teleportation that Wandenreich Quincy are capable of at another point. It all fits very well with whatBleachwould eventually reveal inThousand-Year Blood War, so Kubo’s writing prowess is certainly beyond doubt.