Timeline of Events/Act 1 Timeline

The events that led up to and included the war with Aizen took place over the course of approximately six months during Ichigo's first year in high school. Ichigo became a Shinigami in the middle of May on Friday at approximately 7:13 PM. The timeline of these events is linked to the Japanese school year, with Ichigo acting as Rukia's substitute during the first term of high school (April to mid-July) and going to Soul Society during summer break (mid-July to end of August) with the Arrancar invasion and subsequent battles occurring in second term of high school (Beginning of September to late December). It must be noted that Soul Society anticipated that the decisive battle would take place in winter, but Aizen moved early and the decisive battles instead took place in the middle of October (autumn) instead.