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Tell me about the D in D-Day.

5 minutes | D-Day | Decision Day | Eisenhower | TIME Magazine

Whenever someone says ‘D-Day’, I do get an urge to say, “which-which, D-Day-D are you talk-talking about? 

There were many D-Days during the Second World War. None of the abbreviated forms were shorthand for Decision Day, Doomsday, Dreadnought Day, Die-Hard Day or any other version of an alliterative fronted adverbial. The ‘D-Day’ designation was used liberally throughout, simply to designate a proposed day on which an invasion or important military operation would commence. I’ll say this more than once: ‘D-Day’ is shorthand for Day-Day, which drives, me, nuts.

In this instance— 6th June, 1944, the day our eponymous ‘D-Day’ became enshrined in memory as a definitive 24-hour period— the offensive action was Operation OVERLORD. American, Canadian, and British troops set out for five beaches in Normandy, code-named SWORD, JUNO, GOLD, OMAHA and UTAH. That was June.

Heinz Guderian
However, during the spring, all the elements for that attack still needed discussion. It’s no mean feat to co-ordinate the movements of over 150,000 men as an assault force, nearly 12,000 aircraft and something like 7,000 boats and landing craft, and there were some things the allied commanders simply could not predict. The lunar cycle played a big part in the landings, but that was easy to factor in. High and low tides are regular enough, so they were easy to assess but they could not be certain about the weather. So there had to be some leeway as to the exact date on which an invasion force would cross the Channel. This wasn’t an unusual situation— needing that flexibility— so the team reverted to type. Using a well-established system, they talked about proposed timelines by referring to the day in question as D-Day. The day before it would be known as D-1; two days before the proposed date for action would be D-2; the days after the go-date would be referred to as D+1, D+2 and so on. As I said, ‘D-Day’ means Day-Day. The 6th June was seen as the ideal time-slot for moon and tide. Everything depended on the weather. In his 1948 memoir, ‘Crusade in Europe’, Eisenhower showed his angst at the possibility of delaying the operation. A delay until the next lunar cycle— the 19th— would have been “too bitter to contemplate”, not least because it would have meant wasting valuable long summer days. Our troops would not have fared well in winter conditions. The Commanders in Chief met at Southwick House on the evening of June 4th, D-2, to make a decision on when to set out. Weather reports showed that, after a few hours of rain that evening, there should be at least 36 hours of clear skies and light winds, which could make a June 5th date possible, however… Eisenhower waited. His instincts proved right.

Southwick House was drenched the next morning, so a sea-crossing in those conditions would have done untold damage to our forces. Instead, first thing on the 5th, he canvassed the opinions of each man at the table as to their views on an assault for the 6th June.

Montgomery, leading the assault forces, agreed it should be 6th June. Ramsay, naval Commander in Chief, said it should be 6th June. Air Chief Marshal Sir Trafford Leigh-Mallory passed his judgement— the 6th June— and so it came to pass. D-Day would be, er, D-Day. But those are the facts. Let’s get back to the fiction.

There are some sources— I love the fact we have so many versions of sauces, don’t you? Brown sauce, horseradish sauce, bread sauce in particular— there are some sources that posit alternative meanings for the D in D-Day. One is in a letter written by Brigadier General Robert Schultz, Eisenhower’s executive assistant.
Heinz Guderian
Someone (I haven’t worked out who yet), wrote to Eisenhower in 1964 asking for an explanation. What did the ‘D’ in D-Day stand for, exactly? Schultz is supposed to have replied: “… any amphibious operation has a ‘departed date’, so the shortened term ‘D-Day’ is used.” Hm. I’m not so sure about that. I was wide-ranging on purpose when I described the ‘let’s go, chaps’ concord at Southwick House. The actual words aren’t recorded. In fact, many of Eisenhower’s verbatim comments weren’t recorded with the level of detail that historians appreciate today— certainly not in the same way we have a corpus of Churchillian rhetoric. Self-promotion wasn’t Ike’s style.

In fact, many of Eisenhower’s verbatim comments weren’t recorded with the level of detail that historians appreciate today— certainly not in the same way we have a corpus of Churchillian rhetoric. Self-promotion wasn’t Ike’s style. Still, in his book The Longest Day: The Classic Epic of D-Day, Cornelius Ryan wrote:

“Apart from the four stars of his rank, a single ribbon of decorations above his breast pocket and the flaming shoulder patch of SHAEF (Supreme Headquarters Allied Expeditionary Force), Eisenhower shunned all distinguishing marks. Even in the trailer there was little evidence of his authority: no flags, maps, framed directives, or signed photographs of the great or neargreats who visited him.”

Does that sound like someone who would have asked his executive assistant to clarify the minutiae of a definition with an explanation that wouldn’t stand up to scrutiny? Not really.

Another notion comes from Paul Dickson’s rationale, in his book War Slang: American Fighting Words and Phrases Since the Civil War— a great book for myriad reasons, the least of which is the fact that Dickson cited sources he believed worthy of credit. Dickson writes:

The French maintain the D means ‘disembarkation’, still others say ‘debarkation’, and the more poetic insist D-Day is short for ‘day of decision’.” 

More recently, for TIME Magazine in 2019, Dickson doubles-down: 

“I think ‘disembarkation’ makes more sense because it was an amphibious assault. There was a point in 1940 when they started putting together an army and they had a first draft in anticipation of the Second World War, called M-Day, with the ‘M’ standing for ‘mobilization’. In addition, men in the U.S. between 21 and 35 had to register for the draft on Oct. 16, 1940—which was referred to as R-Day, or ‘registration day’. It was common military parlance, just give something a letter.”

Well yes, but then again, perhaps no. Surely the best time to ask a question, is when the answer is readily available? I believe TIME Magazine itself provided the most reasonable answer. Six days after the event, with little time to fictionalise, this appeared in the letters section of their June 12th issue, 1944:

Everybody refers to D-Day, H-Hour. Can you please tell me what they stand for or how they originated?

“D for Day, H for Hour means the undetermined (or secret) day and hour for the start of a military operation. Their use permits the entire timetable for the operation to be scheduled in detail and its various steps prepared by subordinate commanders long before a definite day and time for the attack have been set. When the day and time are fixed, subordinates are so informed.

So far as the U.S. Army can determine, the first use of D for Day, H for Hour was in Field Order No. 8, of the First Army, A.E.F., issued on Sept. 7, 1918, which read: “The First Army will attack at H–Hour on D-Day with the object of forcing the evacuation of the St. Mihiel salient.”—ED.

So, D-Day does means Day-Day, after all. 🤦‍♀️