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Article: D Day

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D DAY

D DAY. The term "D Day" indicates the beginning of an attack or other military operation when the specific date has yet to be selected or secrecy is required. "H Hour" is similarly used to designate the time of the attack.

The "D" and "H" are derived from the first letters of "day" and "hour." There is one D Day and H Hour for all units participating in an operation. Plus and minus signs are used to indicate the number of days or hours that precede or follow the specific operation. Thus, 舑 5 means five days before D Day and H + 2 means two hours after H Hour.

Planning for operations can begin ...

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