Bleach manga spoiler) Why didn't Ichigo need an Asauchi? - Quora
bleach ichigo new zangetsu | Bleach manga, Manga, Anime
What happened to Ichigo's Shikai? He has his old one again. : r/bleach
Does Ichigo still have dual swords, or does he have his old shikai back? - Quora
Potential theory(might be entirely wrong): ichigo's appearance in the one shot is his true shinigami form and his appearance in the thousand year blood war arc was made by the zero division. :
Bleach: Ichigo's Final Zanpakuto, Explained
Ichigo's Two New Zangetsu's! Juha Bach and Hollow Ichigo – Bleach 542 | Daily Anime Art