March 20th, 1943 (SATURDAY)
UNITED KINGDOM: Despite the successes achieved by U-boats in battles now raging in the Atlantic a new radio-location system has raised Allied hopes of improving their ability to attack enemy submarines. The new system, known as ASV III, operates outside the Metox radio-location detectors which enabled U-boats to avoid aircraft fitted with earlier ASV II systems. ASV III has been fitted to bombers of 172 Squadron, based at Chivenor, Devon, and is being used over the Bay of Biscay.
Minesweeper HMS Rinaldo launched.
GERMANY: Berlin: A second attempt by army officers to assassinate Hitler fails. Colonel Rudolf von Gersdorff's plan to blow himself up with the Führer at a show of weapons captured from the Russians is foiled when Hitler leaves the exhibition before the bomb can be detonated.
TUNISIA: The New Zealand Division reaches the Tebaga Gap in Tunisa. Bombardment begins in the attack on the Mareth Line.
True to form, General Montgomery made no attempt to follow up his success at Medenine. The Mareth Line was his objective, and no one doubted that this was going to be a tough nut to crack. The line was built by the French - against the Italians in Libya - and consists of minefields, anti-tank ditches, barbed wire and carefully concealed artillery positions stretching from the sea to the Matmata Hills in the south.
As the American II Corps, now led by the attack minded Lieutenant-General George Patton Jr, attacks in the north to draw off Axis reserves and 27,000 New Zealanders and 200 tanks make a lengthy outflanking move, Montgomery began his frontal assault today. He is taking a leaf from Alamein, using infantry - three divisions of Lieutenant-General Sir Oliver Leese's XXX Corps - to create a gap for X Corps under Lieutenant-General Brian Horrocks.
Although the infantry has succeeded in getting a foothold in the enemy lines, the tanks have been baulked by mines and the soft going of the Wadi Zigzaou. The infantry, concentrated in a relatively small area, is coming under heavy fire from German artillery. As dusk falls over Mareth, Montgomery is preparing a fresh attack.
Lt-Col. Derek Anthony Seagrim (b.1903), Green Howards, led his battalion with great valour in combat which led to the capture of a key objective. (Victoria Cross)
PACIFIC OCEAN: During the night of 20/21 March, 40 US Marine Corps and Navy Grumman TBF Avengers drop forty 1,600-pound (730 kg) antishipping mines in the southern Bougainville area of Buin-Tonolei. The Thirteenth Air Force dispatches 18 B-17s and B-24s to hit Kahili Airfield on Bougainville in a diversionary strike.
CANADA: HMCS Griffin renamed HMCS Ottawa.
U.S.A.: The United States offers to act as an agent between Soviet Union and Finland in preparing the peace. (Gene Hanson)
New Haven, Connecticut: The Big Band leader and Captain in the United States Army Air Force, Alton G. "Glenn" Miller, creates a special 50-member band, the 418th Army Air Force Band. Their post duties include reveille, taps, march, retreat and entertainment.
Destroyer escort USS Breeman laid down.
Destroyers USS Ammen and Dashiell commissioned.
Submarine USS Billfish commissioned.
Destroyer escort USS Edgar G Chase commissioned.