http://www.onwar.com/chrono/1941/apr41/f13apr41.htm
Japan and USSR sign neutrality pact
Sunday, April 13, 1941 www.onwar.com
In Moscow... The USSR and Japan sign a five year Neutrality Agreement. For Stalin this is an invaluable piece of diplomacy which, backed by secret information from Soviet spies in Tokyo, will allow him to transfer forces from Siberia to face a possible German attack. These moves begin now. The agreement represents a complete change in Japanese policy and marks the growing concern of the Japanese military leaders and statesmen to look south to the resources of the East Indies. The agreement has been negotiated almost alone by Foreign Minister Matsuoka, in Moscow on the way back from a European visit.
In the Balkans... In Greece, the withdrawal to the Mount Olympus position is not yet complete but the British and Greeks decide that they must retreat farther to shorter lines near Thermopylae.
In North Africa... German-Italian attacks on Tobruk are held.
http://homepage.ntlworld.com/andrew.etherington/month/thismonth/13.htm
April 13th, 1941
GERMANY: Berlin: The Wehrmacht High Command announced:
Yesterday the Luftwaffe again inflicted heavy losses in repeated raids on the remains of the Serbian army. Dive-bomber, destroyer and fighter aircraft cut enemy march columns to pieces in the lower Bosnia valley and in the area between the Sava and Drin rivers. Ground-attack aircraft bombed military installations around Sarajevo and scored bomb hits on aircraft stationed on the ground at Mostar airfield. Other Luftwaffe formations blew up Greek troop assemblies at Deskati. In the Lake Prespa area, German fighter planes shot down 6 British Bristol Blenheims. In bomb raids on Piraeus harbour, the Luftwaffe sank four merchant vessels totalling 35,000 tons, badly damaged eight large merchant vessels, and set the harbour installations on fire. During the last two nights, heavy calibre bombs hit a destroyer and 3 large merchant ships in the inlet at Eleusis and outside the port of Piraeus. Another effective high-explosive bomb raid was made on Eleusis airfield.
Berlin: Hitler orders swift mopping-up operations in Yugoslavia and Greece.
U.S.S.R.: Moscow: In a treaty designed to safeguard both parties’ borders, the Soviet Union and Japan today signed a neutrality pact, valid for five years.
By acknowledging existing borders the pact, negotiated by Molotov, give Russian recognition to Japanese Manchuria (now known as Manchukuo) for the first time. Under the pact, should either the Soviet Union or Japan become the object of military action, then the other party will observe neutrality.
The impetus came from Russia, increasingly concerned by the deterioration of its relationship with Germany. In Tokyo the pact was welcomed as guaranteeing Japan’s “back door”.
This means that Stalin can begin troop movements east and that Japan can look south.
YUGOSLAVIA: German and Hungarian troops enter Belgrade.
GREECE: General Wilson decides to withdraw to the Thermopylae line - running from the town of Molos on the Gulf of Euboea east of Thermopylae, to Eratine on the Gulf of Corinth.. This is a naturally strong defensive line, and had the merit of being only 50 miles long (compared with the 100 miles of the Olympus-Vermion line) and could in theory be held by the British troops on their own.
MALTA: The island is heavily bombed by the Luftwaffe.
LIBYA: The Germans capture Sollum and Fort Capuzzo.
ATLANTIC OCEAN: AMC HMS Rajputana on Northern Patrol is lost to U-108 in the Denmark Strait.
One of the motivations for Hitler declaring war on the US after Pearl Harbor, was that he hoped it would lead the Japanese to enter the war against the Soviet Union, of course they didn't fall for it.