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September 1:
- Nothing happened on this day in Kingdom Hearts history!
September 2:
- Nothing happened on this day in Kingdom Hearts history!
September 3:
- Kingdom Hearts Unchained χ released in Japan on this day in 2015!
September 4:
- Nothing happened on this day in Kingdom Hearts history!
September 5:
- Nothing happened on this day in Kingdom Hearts history!
September 6:
- Nothing happened on this day in Kingdom Hearts history!
September 7:
- Kingdom Hearts Birth by Sleep released in North America on this day in 2010!
September 8:
- Nothing happened on this day in Kingdom Hearts history!
September 9:
- Kingdom Hearts Birth by Sleep released in Australia on this day in 2010!
September 10:
- Kingdom Hearts HD 1.5 ReMIX released in North America on this day in 2013!
- Kingdom Hearts Birth by Sleep released in Europe on this day in 2010!
September 11:
- Nothing happened on this day in Kingdom Hearts history!
September 12:
- Kingdom Hearts HD 1.5 ReMIX released in Australia on this day in 2013!
September 13:
- Kingdom Hearts HD 1.5 ReMIX released in Europe on this day in 2013!
September 14:
- Nothing happened on this day in Kingdom Hearts history!
September 15:
- Nothing happened on this day in Kingdom Hearts history!
September 16:
- Nothing happened on this day in Kingdom Hearts history!
September 17:
- Kingdom Hearts released in North America on this day in 2002!
September 18:
- Nothing happened on this day in Kingdom Hearts history!
September 19:
- Nothing happened on this day in Kingdom Hearts history!
September 20:
- Square Enix announces Kingdom Hearts 358/2 Days, Kingdom Hearts coded, and Kingdom Hearts Birth by Sleep at Tokyo Game Show on this day in 2007!
September 21:
- Nothing happened on this day in Kingdom Hearts history!
September 22:
- Square Enix Holdings was founded on this day in 1975!
September 23:
- Nothing happened on this day in Kingdom Hearts history!
September 24:
- Nothing happened on this day in Kingdom Hearts history!
September 25:
- Nothing happened on this day in Kingdom Hearts history!
September 26:
- Square Enix announced Kingdom Hearts Chain of Memories and Kingdom Hearts II on this day in 2003!
September 27:
- Nothing happened on this day in Kingdom Hearts history!
September 28:
- Kingdom Hearts II released in Australia on this day in 2006!
September 29:
- Kingdom Hearts 358/2 Days released in North America on this day in 2009!
- Kingdom Hearts II released in Europe on this day in 2006!
September 30:
- Nothing happened on this day in Kingdom Hearts history!