Three Months at N2

Last month was the 60th anniversary of the bombing of Hiroshima and Nagasaki, once again begging the question… Should we have dropped the bomb?

A rough timeline outlining the 1945 bombing is as follows:

July 16th: Trinity Test – first successful atomic bomb test.

August 6th: Hiroshima bombing. 100,000 people killed instantly.

August 9th: Nagasaki bombing. 80,000 people killed instantly.

August 9th: USSR declares war on Japan.

August 14th: Japan surrenders / fighting stops.

September 2nd: USA officially accepts the surrender of Japan.

It is often suggested, knowing that the USSR was going to enter the war, and that Japan could not possibly defeat both enemies, that the Hiroshima and Nagasaki attacks were unnecessary. There are, however, some problems with that line of reasoning.

The Samurai code had had a strong cultural influence on the Japanese. They had often claimed that to them, dying was preferable to losing the war. What we had seen while taking Okinawa bore that out. The Japanese had begun loading Kamikaze (suicide) planes with explosives and ramming them into the US fleet, and the fighting on land had been the fiercest yet of the entire war. The fact that the Japanese ultimately surrendered might seem to be proof that death was not in fact preferable. This is a common error in logic. The truth is that even at the moment of surrender, the Japanese likely still would rather have died than lose.

But dying to prevent losing the war was not an option they had. By August 10th it was likely quite clear that they were going to lose. The choice they had was to lose and live, or lose and die. The fact that they were prepared to die to avert loosing was no longer sufficient. Losing had become inevitable.

It appears likely that they would not have surrendered until victory was truly beyond all hope.

Based on the experience in Okinawa, and given the sacrifices the Japanese were willing to make, conservative estimates suggested that taking the Japanese mainland would cost the lives of 250,000 US troops, 3 Million Japanese troops, and 1 Million Japanese civilians (who had thrown themselves from cliffs rather than be captured).

Roughly 38 Million people had already lost their lives in World War II. The idea of decisively ending the war at a cost of 200,000 enemy lives probably seemed reasonable.

One must also remember that it was a war. Gambling 250,000 American lives on whether or not Japan would surrender when the USSR entered the war would not be particularly good war planning. Not finishing off an enemy because you assume that they will surrender isn’t so smart either. Such assumptions have lost many a country many a war. The Japanese were an industrious people, and assuming they were finished before it was true could have been a huge mistake.

In fact, there is considerable evidence that it would have been a mistake, that the Japanese did have hopes of beating the combined forces of the USA and USSR. Though it seems impossible, there was one way they thought they could…

With nuclear weapons…

A little known fact (even after being published by the AP and the Japan Times⁽¹⁾Hall, K. (2003, March 7). Wartime Documents Set Record Straight. The Japan Times) is that the Japanese had two active nuclear weapons programs in 1945, with the goal of developing a 20kT bomb nearly 40% larger than the Hiroshima device.

The first program was started by the army in the spring of 1941, and was based in the Rikin Laboratory in Tokyo. Though progress was steady (and possibly assisted in by a US spy from Los Alamos) they suffered continual supply problems. They had hoped to solve these problems with 560kg of uranium from Germany⁽²⁾Benke, R. (1997, June 1). New Evidence Tracks Japan’s Efforts to Create Atomic Bomb. ASSOCIATED PRESS, but the sub carrying the shipment, U-234, was seized by the Americans before it could get to Japan. The program finally ended in failure when the Rikin lab was destroyed in the fire-bombing of Tokyo on April 14th, 1945.

However the second program, run by the Japanese Navy⁽³⁾Physics Daily, had considerably greater success. Anticipating the possibility of bombing in Tokyo, the project was halted for three months and moved to the N2 lab in Japanese occupied North Korea, where bombing was less likely, and labor and uranium were more plentiful.

On August 12, 1945, there was a report that Japan detonated a nuclear blast off of the coast of Konan⁽⁴⁾Snell, D. (1946, October 2). Japan Developed Atom Bomb; Russia Grabbed Scientists. The Atlanta Constitution, less than a month after the US Trinity test. Japan had become a nuclear power just two days before it surrendered.

On August 5th, the Japanese plan to win the war was not unreasonable⁽⁵⁾Japan’s Atomic Bomb. It would take one to three months to make nuclear weapons which could be deployed in the field. They would hold off the invasion of the mainland while they made two bombs. They would then detonate one in the middle of the US Pacific fleet and one in San Francisco. To that end they had built a submarine, which could hold and launch aircraft, to carry a plane and the bomb to the United States. With the US Fleet gone, they would have enough time to make dozens of nuclear bombs.

However, after the destruction of Hiroshima and Nagasaki, it became clear to them that despite the successful nuclear test, by the time they built a deployable nuclear weapon, there would be no Japan left to defend. The US had won a nuclear race it didn’t even know it was in.

Had the moving of the N2 lab taken less than three months (or had the US not attacked Hiroshima and Nagasaki), it is quite possible that Japan would have successfully built and deployed two or more nuclear weapons against the United States. We would likely still have won the war (by all accounts we had more uranium and could build bombs faster than they could), but not without our own deployments. The result would be a nuclear war with a total of 5-8 deployments before the Japanese surrender.

Truman had no idea that the Japanese even had a nuclear weapons program. Fortunately, however, he didn’t take the risk.