Indian Ocean raid

Indian Ocean raid
Part of World War II, Pacific War
British heavy cruisers HMS Dorsetshire and Cornwall under Japanese air attack and heavily damaged on 5 April 1942.
Date 31 March – 10 April 1942 Location Indian Ocean and Ceylon Result Japanese victory
Belligerents
United Kingdom  Australia  Netherlands  United States  Canada	Japan
Commanders and leaders
James Somerville	Chūichi Nagumo
Strength
2 fleet carriers 1 light carrier 5 battleships 7 cruisers 15 destroyers 7 submarines 100+ aircraft 30 smaller warships 50+ merchant ships	5 fleet carriers 1 light carrier 4 battleships 7 cruisers 19 destroyers 5 submarines 350 aircraft
Casualties and losses
1 light carrier sunk 2 heavy cruisers sunk 2 destroyers sunk 1 Armed Merchant Cruiser (AMC) sunk 1 corvette sunk 1 sloop sunk 23 merchant ships sunk 40+ aircraft destroyed	20+ aircraft destroyed

The Indian Ocean raid (known in Japan as Operation C) was a naval sortie by the fast carrier strike force of the Imperial Japanese Navy from 31 March to 10 April 1942 against Allied shipping and bases in the Indian Ocean. It was an early engagement of the Pacific campaign of World War II. The Japanese under Chūichi Nagumo compelled part of the Allied (largely Royal Navy) forces to retreat to East Africa, but Admiral Sir James Somerville kept his fast carrier division, Force A, "...in Indian waters, to be ready to deal with any attempt by the enemy to command those waters with light forces only."

The island of Ceylon was strategically important, since it commanded the Indian Ocean. Thus it controlled access to India, the vital Allied shipping routes to the Middle East and the oilfields of the Persian Gulf. Ceylon held most of the British Empire's resources of rubber. An important harbour and naval base, Trincomalee, was located on the island’s eastern coast. Japanese propaganda had an effect on some of the Sinhalese population, who now awaited their arrival.

The fall of Singapore on 15 February 1942 broke the United Kingdom's eastern defensive perimeter of the Bay of Bengal; and Japanese occupation of the Andaman Islands on 23 March 1942 gave Japan control of the Andaman Sea enabling ships to resupply Japanese troops in the Burma Campaign for control of India. Both German and British authorities anticipated Japanese capture of Ceylon to solidify control of the Bay of Bengal and disrupt British resupply for defence of India, Australia, and perhaps the Middle East. Ceylon was hastily garrisoned by Australian troops returning from North Africa; and HMS Indomitable was relieved of naval duties to serve as a high-speed aircraft ferry shuttling available planes to Ceylon.

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