Nach einem rechtzeitig abgebrochenen Angriff auf ein alliiertes Lazarettschiff am 1.2. torpediert Ro-50 (Kptlt. Kimura).
Japanese tanker No.26 Nanshin Maru is sunk by mine eat of Nansei Shoto, Ryukyu Islands. The guardboat No.15 Shinko Maru rescued the survivors.
Japan Japanese vessel No. 26 Nanshin Maru sunk by mine
Yellow Sea Japanese vessel No. 16 Nissho Maru sunk by mine west northwest of Mokpo, Korea, 35°00’N, 125°00’E.
South China Sea Japanese vessel Taietsu Maru, previously damaged by USN submarine Boarfish and run aground off French Indochina, sunk by US 14th Air Force, directed to the scene by Boarfish (SS-327)
HMS Spark sinks Japanese towboat No.203 Katsura Maru and damages motor sailboats Nanyo Maru, Nampo Maru and No.80 Tachibana Maru off Jabara, 06°41’S, 110°32’E.
Brit. U-Boot-Operationen in der Strasse von Malakka und im Westteil des Malaya-Archipels:
Spark (Lt Kent) versenkt am 1.2. in der Javasee einen Routendampfer, einen Schlepper und einen Leichter und beschädigt einen weiteren Routendampfer. Tantalus (LtCdr. Mackenzie) versenkt am 1.2. einen Schlepper und drei Leichter.
HMS Spark (P 236), commanded by Lt. Commander Derrick G. Kent, sank a Japanese coaster and a barge that the coaster was towing and a Japanese tug with gunfire in the western part of the Java Sea. An additional coaster was forced ashore on Panjang Island. Another coaster was finally destroyed on the beach and left as a total loss.
HMS Tantalus (P 318), commanded by Lt. Commander Hugh S. Mackenzie, sank a Japanese tug and three barges in the southern part of the South China Sea.
USS PT-77 (USN): The Higgins 78’ -class PT Boat was shelled and sunk by USS Conyngham and USS Lough off Talin Point Luzon.
USS PT-79 (USN): The Higgins 78’ -class PT Boat was shelled and sunk by USS Conyngham and USS Lough off Talin Point Luzon.
T-115 (IJN): The No.103-class landing ship was bombed and sunk in the Balintang Channel Luzon Strait in the South China Sea (20°00′N 121°00′E) by P-51s of the 3rd and 4th Squadrons, 3rd Air Commando Group, USAAF
B-24 and B-29 bombers raid Iwo Jima in preparation for the landings later in the month. They drop a daily average of 450 tons of bombs over the course of 15 days (6800 tons).
China Hunan-Kwangtung-Kiangsi operations: 57th Infantry Brigade of Japanese 20th Army captures Tungkiang
Formosa US FEAF aircraft attack Heito and Okayama
Burma Indian 15th Corps captures Sane on Ramree Island
Japanese Matsu Detachment counterattacking Indian 15th Corps around Kangaw
US 10th Air Force provides support for ground operations around Hosi and Molo with 28 fighters, attacks Mong Pawn bridge with 12 bombers, Japanese positions, airfields, transportation lines, and other targets around Nauchye, Hsenwi, Man Pwe, Pongkalau, Nawng Mawn, Na-lang, Kunhkan, and Panghtu-lin with more than 90 fighters
RAF aircraft attack airfields at Meiktila, Heho, and Anisakan
The Fourteenth Army, under command of Lieutenant-General Sir William Slim, had closed up to the Irrawaddy River from a point 40 miles north of Mandalay to Pakokku, 140 miles downstream.
US 6th Army pushing rapidly toward Manila and attacking around Zigzag Pass on Luzon
11th Airborne Division of US 8th Army held up around Mt Cariliao and Mt Batulao south of Manila on Luzon
US FEAF aircraft attack Cavite naval base, Corregidor Island, Palawan Island and other targets
US 7th Air Force attacks Corregidor Island with 20 bombers overnight
Japanese vessel T-115 sunk and escorting submarine chaser Ch 28 damaged by USAAF P-51s in Luzon Straits
Destroyers Jenkins (DD-447), O’Bannon (DD-450), and Bell (DD-587), and destroyer escort Ulvert M. Moore (DE-442) sink submarine RO 115, 125 miles southwest of Manila, 13°20’N, 119°20’E.
USN PT-77 and PT-79 damaged by friendly fire from the destroyer USS Conyngham (DD 371) and the destroyer escort USS Lough (DE 586) near Talin Point, Luzon, / off Mindoro Island
The American advance on all fronts is slowed by fierce Japanese resistance. US 1st Corps is heavily engaged near Rosario and San Jose while US 11th Corps is struggling to make more ground across the neck of the Bataan Peninsula.
U.S. Rangers and Filipino guerrillas rescue 513 American survivors of the Bataan “death march”
Singapore US 20th Air Force attacks targets (shipping and harbor facilities) in and around Singapore with 109 B-29 bombers. Oiler Shiretoko, 01°20’N, 103°50’E damaged.
XX Bomber Command conducted a major conventional bombing raid on Singapore Naval Base on 1 February. On that day, 112 B-29s were dispatched, each armed with four 1,000 lb (450 kg) bombs. The raid's primary target, the Admiralty IX Floating Dock, was bombed by 67 of the 88 aircraft that reached Singapore. This attack sank the dry dock and destroyed the 460 ft (140 m) ship berthed inside it. The other 21 aircraft that attacked Singapore bombed the West Wall area of the naval base and destroyed many buildings and some heavy equipment; this area housed the base's main offices. Of the remaining aircraft, 20 diverted and attacked targets in Penang and Martaban. A Japanese fighter shot down one of the B-29s and another Superfortress was destroyed on landing after suffering damage from air attack. 
USS Sea Cat departed Guam, Mariana Islands for her second war patrol.
USS Segundo departed Guam, Mariana Islands for her third war patrol.
Commander Jacob Wilson Waterhouse relieved Commander Hinton A. Owens as the commanding officer of USS Luce.
Captain Thomas Howell Binford was named the commanding officer of USS Miami while the ship was at sea south of Tokyo, Japan.
Light carrier Hosho arrived at Tokuyama, Japan, refueled, and departed to conduct a training exercise as a target vessel.
The Taiwan District Army was formed within the Japanese Tenth Area Army with the former commanding officer General Rikichi Ando of the former Taiwan Army at its head.
US Nishmaha, Freighter (Chronological List of U.S. Ships Sunk or Damaged)
USN Overseas Aircraft Loss List
Ecuador declares war on Germany and Japan.