I fancy myself as a competent bridge player in spite of all evidence to the contrary and read the daily bridge column in the Albuquerque Journal. It is the nationally syndicated column, Aces of Bridge, by Bobby Wolff. Mr. Wolff’s December 27, 2017 Column included the following quote from Edgar Rice Burroughs: “I do not think that I am ever overconfident. I am merely wholly confident, and I maintain that there is all the difference in the world there.” 

Burroughs played bridge regularly while in Hawaii (according to Taliaferro in Tarzan Forever), but there is no empirical evidence about his skill level. In ERBzine 2792, Edgar Rice Burroughs' Wartime Autograph Book Series BOOK No. 4 ~ 1944 ~ Part 6: June, from Danton Burroughs Tarzana Archives, the following quotes and references appear:

Elise "Granny" Davis: “To a nice guest though "poor" bridge player. 6-5-44 
Aloha to a new bridge foursome!” - Nora Davies Burton - Honolulu - June 5, 1944 
Ed: Dinner and bridge with Bruce Cruikshank.

June 5, 1944 Entry in ERB's Wartime Autograph Book: ERBzine 2792

The 1940 census shows that Bruce Cruikshank was 36 years old in 1940 and lived at 645 Mahalo Street, Honolulu. My research turned up information that indicated that Mr. Cruikshank died in Hawaii in 1977, but little other information. 

Nora Davis Burton, 88, a Washington area volunteer and the wife of a Marine Corps officer, died December 14, 2006, of ovarian cancer at her home in Fairfax City, Virginia. She had lived in Northern Virginia since 1959. 

Mrs. Burton was born in Honolulu in what was then the territory of Hawaii. After graduating from high school in 1936, she married a Marine Corps lieutenant. The couple lived in Virginia, South Carolina and Cuba before being transferred back to Hawaii, six days before the Japanese attack on Pearl Harbor. 

During World War II, Mrs. Burton volunteered with a Honolulu blood bank while her husband fought in the South Pacific. She continued her volunteer work during her years in Northern Virginia, volunteering with the Red Cross at Quantico, serving as a member of the Altar Guild of St. Andrew's Episcopal Church in Arlington County and driving for Meals on Wheels.

During World War II, Mrs. Burton volunteered with a Honolulu blood bank while her husband fought in the South Pacific. She continued her volunteer work during her years in Northern Virginia, volunteering with the Red Cross at Quantico, serving as a member of the Altar Guild of St. Andrew's Episcopal Church in Arlington County and driving for Meals on Wheels. 

Her husband, retired Brigadier General Custis Burton Jr., died in 1991. 

Elise P. Davis was born in California in 1898 and lived in Honolulu during WWII. She was married to Foster Davis and they had one child, also named Foster Davis. 

So we know that ERB played bridge with these three people on June 5, 1944 and at least one of the four didn’t think ERB was much of a player. Of course, ERB’s attention to the game may have been less than focused. As a war correspondent, he may have been watching the European Theater. Things were a little busy “over there”.

On the morning of June 5, 1944, U.S. General Dwight D. Eisenhower, the supreme commander of Allied forces in Europe gave the go-ahead for Operation Overlord, the largest amphibious military operation in history. On his orders, 6,000 landing craft, ships and other vessels carrying 176,000 troops left England for the trip to France. That night, 822 aircraft filled with parachutists headed for drop zones in Normandy. An additional 13,000 aircraft were mobilized to provide air cover and support for the invasion.

By dawn on June 6, 18,000 parachutists were already on the ground; the land invasions began at 6:30 a.m. The British and Canadians overcame light opposition to capture Gold, Juno and Sword beaches; so did the Americans at Utah. The task was much tougher at Omaha beach, however, where 2,000 troops were lost and it was only through the tenacity and quick-wittedness of troops on the ground that the objective was achieved. By day’s end, 155,000 Allied troops–Americans, British and Canadians–had successfully stormed Normandy’s beaches.

I’m not sure how well ERB’s evening of bridge turned out, but Eisenhower bid and made a grand slam doubled and redoubled. There are hundreds of books that go into detail about Eisenhower’s activities on June 5th and 6th. The time difference between London and Honolulu is ten hours.

06:30 June 6th London time was H-Hour on Omaha, Utah, Juno, Gold and Sword beaches. The 1st and 29th American Divisions landed over a four-mile front at Omaha. The US 4th Division assaults Utah. 

It was ten hours earlier at the Davis residence in Hawaii. At 8:30 PM, Aloha time, Edgar Rice Burroughs and his companions were enjoying and evening of dinner and bridge while the first D-Day landings took place.

His hostess’s husband, was Marine Lieutenant Colonel Curtis Burton Jr. He commanded the 2nd Provisional Field Artillery Group, which contained three batteries of 155mm howitzers and three of the 155mm ‘Long Tom” guns during the assault on Okinawa.

During the Korean War conflict, now Colonel Burton and Colonel Frank P. Hagar performed the task of G-4 until they were assigned commands of the 5th and 11th Marines, respectively. Burton became chief-of-staff in February 1952. G-4 was logistics and services.

One last bit of information about General Burton. The following is from his meritorious award citation: 

The President of the United States of America takes pleasure in presenting the Legion of Merit with Combat "V" to Colonel Custis Burton, Jr. (MCSN: 0-5104), United States Marine Corps, for exceptionally meritorious conduct in the performance of outstanding services to the Government of the United States while serving with the FIRST Marine Division in action against the enemy in Korea during the period 4 August 1951 to 19 November 1951. Serving as Commander of a Marine Artillery Regiment, Colonel Burton consistently displayed outstanding skill, courage, and confidence in the operation of his regiment. A most capable and inspiring officer, wise and persevering in maintaining continuous artillery support to ground elements, his meticulous attention to detail and expert tactical abilities contributed essentially to the many tactical successes achieved by the Division. Colonel Burton's skilled service and exemplary conduct throughout were in keeping with the highest traditions of the United States Naval Service. (Colonel Burton is authorized to wear the Combat "V".) 

All that information from autographs referencing a simple game of cards. 

I decided to include an ERB quotation from the Hawaii years. From the Honolulu Advertiser, December 15, 1941, in his column, “Laugh It Off”, ERB replies to a radio propaganda broadcast from Japan. He refers to the propagandist as Baron Hee Haw, the Little Bad Wolf. The article was reprinted by Honolulu Star-Bulletin on December 18, 1941. The Star-Bulletin ran the column for a couple more years. Please note that this column appeared eight days after the attack on Pearl Harbor. Ref: ERBzine 1754

“We are not an understanding people. We are too dense to realize that Japan was bringing peace and prosperity to the island of Oahu last Sunday. We may be dumb, but we remember. We remembered the Alamo, we remembered the Maine, we shall remember Pearl Harbor. Behind our kidding and joking, there is an iron will, and backing that up will be a splendid arm, a grand navy. So talk on little man, and give us more laughs.”

Burroughs use of the phrase, “Remember Pearl Harbor surprised me. For some reason I had mistakenly believed Roosevelt used the phrase in his “Day of Infamy” speech. He didn’t. I searched for an earlier printed use of the phrase “Remember Pearl Harbor”, but I didn’t find one. There’s probably one somewhere, but for now the December 15, 1941 article by ERB is the first one I can find. Was he the first person to write “Remember Pearl Harbor?” I don’t know. It could be. He always did have a way with words.

From the Honolulu Advertiser, July 4, 1942, “Don’t Be Stupid”. Ref:  ERBzine 1756

“The extent of millions of square miles of ocean is difficult to conceive. So let’s reduce that to 598 square miles of Oahu and everything else more or less in proportion. You are observing from a Flying Fortress of microscopic dimensions. It is probably much smaller than a gnat. The enemy force consists of two carriers, four cruisers, and eight destroyers. The carriers are the size of ants. The other ships are smaller ants. They are somewhere on Oahu and you go out looking for them. It is raining and a heavy mist is rising from the ground. Would you be surprised if the ants reached their objective unobserved?
Don’t throw away your gas mask. Don’t cancel your mainland booking. Don’t neglect your defense duties. Don’t me stupid. The Japs might come tomorrow.”