by RockyMountainNavy, 5 March 2025
The account of the Battle of the Bismarck Sea that appears in Helmut Pemsel’s A History of War at Sea is less than dramatic:
2-5 March 1943: Air-sea action in the Bismarck Sea. The Japanese send a convoy of 8 transports, escorted by destroyers, to reinforce their garrisons in New Guinea. US Army and Australian bombers attack the convoy, and sink all the transports and 4 destroyers. A whole Japanese division is lost. (Pemsel, p. 139)
The complete story of the Battle of the Bismarck Sea is, however, much more than that simple passage above. If you are a wargamer that relishes air-sea battles, the Battle of the Bismarck Sea should be fought on your table.
John Prados in Combined Fleet Decoded helps set the stage for the battle which was enabled through solid Allied intelligence work. In February 1943, the Imperial Japanese Army decided to reinforce New Guinea with an entire infantry division. The 51st Infantry Division was detailed to sail through the Bismarck Sea. For expediency’s sake the division was to be moved in a single convoy. Reconnaissance aircraft from the U.S. Fifth Air Force detected evidence of the coming convoy when they noticed increased concentrations of shipping in mid- and late-February. Signals intelligence (SIGINT) also revealed plans to move a convoy in early March with a further two divisions to move later in the month. SIGINT even revealed the convoy’s size and timetable. To cover their sources, Fifth Air Force stepped up patrols hoping to “catch” the convoys. (Prados, pp. 449-450)
The Japanese Imperial Navy assigned eight destroyers to escort the eight transports carrying 6,900 troops. The Japanese ordered airstrikes on Allied airfields in conjunction with the convoy’s sortie. Both the Japanese Naval Air Force and Japanese Army Air Force planned to cover the convoy with 200 fighters. (Prados, pp. 450-451)
The convoy set sail around local midnight on 28 February. The planned Japanese airstrikes for the next day did not take place due to weather. Of the 200 fighter sorties promised less than 80 actually flew; those that did found communications challenged thanks to incompatible radios. (Prados, pp. 450-451)
U.S. B-24 reconnaissance aircraft located Convoy Number 81 in the late afternoon of 1 March. The next morning (2 March) a high-altitude attack by B-17 bombers resulted in one transport sunk. The Japanese convoy commander detached two destroyers to collect some 950 survivors as the rest of the convoy sailed on. Those two destroyers and their rescued survivors would be the only ones to arrive at their destination. (Prados, p. 450)
On the morning of 3 March, Fifth Air Force bombers struck the Japanese convoy. As the nearly 100 Allied aircraft approached the few Japanese fighters covering the convoy remained at high-altitude planning to defend against the expected B-17 bombers. On this day, however, the Japanese faced a new threat—from down low. U.S. Fifth Air Force commander General George C. Kenney had experimented with low altitude bombing. As Ronald Spector explains in Eagle Against the Sun:
Although Arnold and other air force leaders continued to swear by high-altitude bombing, Kenney almost immediately began to experiment with low-level antishipping strikes. The B-25 medium bomber was modified to cary eight forward-firing machine guns and six one-hundred-pound bombs, and sixty small fragmentation bombs with delayed action fuses.
All through the fall and into the winter of 1942-43, Kenney’s squadrons practiced attacks from 150 feet up, using an old ship wrecked off Port Moresby as their target. The planes came in so low that two were hit by flying debris and another hit the old ship’s mast, but by the beginning of 1943 they had become the deadliest naval weapon MacArthur possessed. By the time the convoy carrying General Adachi’s troops was sighted, Kenney’s flyers were itching to fight. (Spector, p. 227)
Other sources describe the new “skip bombing” B-25 modifications as replacing the bombardier’s glazed nose with eight 50-caliber machine guns for strafing decks and skipping 500 pound bombs with a delayed fuse into the sides of target ships. Regardless of the technical details, the fact is that the tactic was extremely effective this day (Dull, p. 269).
As the Japanese fighter cover perched high and tangled with Allied fighters, the B-25s, A-20’s, and Australian Beaufighters swept in low and struck. The Japanese, having never before faced “skip bombing,” thought they were facing torpedo bombers and responded in a way that simply presented themselves to another striking aircraft. As a result, all seven remaining Japanese transports and four destroyers were sunk. The surviving destroyers picked up 2,427 troops from the water and fled back to where they came from. (Spector, p. 228; Prados, p. 450)
Sink the Bismarck Sea
For wargamers, the Battle of the Bismarck Sea offers several different gaming opportunities. At a very tactical scale, wargames like J.D. Webster’s Whistling Death (Clash of Arms, 2003) provide a very granular view of getting aircraft into attack positions to properly deliver their bombs. Running a scenario with the Admiralty Trilogy Group’s rule set Command at Sea, 4th Edition (2008) is still detailed but shows more of the ship-side of the battle. Lee Brimmicombe-Wood’s Wing Leader series from GMT Games is a step-up in abstraction but still a very engaging grand tactical depiction of the battle—the “side view” of the battle helps visualize the skip bombing in action. Moving up to the operational scale of wargames, the search phase can be played out in more detail but the “tactics” of the battle, i.e. skip bombing, tends to get lost or at best is reduced to a die roll modifier.
A Battle of the Bismarck Sea scenario is ripe for “what if” testing. What if the Japanese airstrikes hit the Allied bases? What if the Japanese air cover was effective? What if the bombers were not as proficient at skip bombing? What if the escort was beefed up? So much gaming potential… .
Sources consulted
- Dull, Paul S. (1978) A Battle History of the Imperial Japanese Navy (1941-1945). Annapolis: Naval Institute Press.
- Pemsel, Helmut (1975) A History of War at Sea: An atlas and chronology of conflict at sea from earliest times to the present. Annapolis: Naval Institute Press.
- Prados, John (1995) Combined Fleet Decoded: The Secret History of American Intelligence and the Japanese Navy in World War II. New York: Random House.
- Spector, Ronald H. (1985) Eagle Against the Sun: The American War with Japan. New York: Vintage Books (Random House).
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Great story. Very sad for the Japanese. And I generally don’t feel sad for the Japanese in World War II but they really had no chance
I have played this using avalanche presses second world war C series. I cobbled together a scenario out of South Pacific. If you do it on vessel, you can actually get the right numbers of aircraft. Each step is six aircraft in the APL games, but you can pick as many as you want in Vassel so you’re not limited by how many B 25 counters or bo fighter counters he might have