Ask which air attack killed the most people in one go and most people will say Hiroshima. The answer is arguably this raid, five months earlier, using ordinary incendiary bombs, and almost nobody outside Japan can name it.
What happened
On the night of 9 to 10 March 1945, 334 US B-29 bombers attacked Tokyo in an operation code-named Meetinghouse. They dropped about 1,665 tons of incendiaries.
Two decisions made it what it was. The aircraft flew at low altitude rather than high, which greatly increased accuracy and bomb load. And they attacked at night with incendiaries rather than high explosive, against districts built largely of wood and paper.
What incendiaries do to a wooden city
The individual fires merged. A firestorm generates its own wind, drawing air inward at gale force and raising temperatures past the point at which anything organic survives. People died of burns, of asphyxiation as the fire consumed the oxygen, and by drowning in canals and rivers they entered to escape the heat.
Roughly 100,000 people were killed in a single night, and more than 15 square kilometres of Tokyo ceased to exist. Around a million people were left homeless.
How it compares with the atomic bombings
| Tokyo, 9–10 Mar 1945 | Hiroshima, 6 Aug 1945 | |
|---|---|---|
| Killed | about 100,000 | 90,000 to 166,000 by year end |
| Weapon | 1,665 tons of conventional incendiaries | One bomb, about 15 kilotons |
| Aircraft | 334 | 1 |
| Duration | A night | An instant, then months |
| Long-term effects | Burns and displacement | Radiation illness over decades |
The tolls are comparable. What differs is the machinery required and what the weapon kept doing afterwards. Hiroshima is covered here.
Set that against the other entries in this index: it exceeds every incident outside the atomic bombings combined.
Why nobody remembers it
Several reasons, and none of them is that it was smaller.
- No new weapon. Incendiaries were already in use across Europe and Japan, so the raid marked no threshold.
- No lasting physical trace. A burned district is rebuilt; a hypocentre becomes a memorial.
- No continuing illness. There was no cohort of survivors under medical study for decades.
- It did not end the war, so no argument about necessity attached itself to it.
The result is that the deadliest raid in history is a footnote, which says more about how atrocities enter memory than about the raid. The archive's page on why some events register and others do not describes the same mechanism.
Which category this belongs in
The third column, with the atomic bombings. The target was a district of a city, selected because it would burn. Civilians were not incidental to the plan; the flammability of the housing they lived in was the plan.
What area bombing means
An attack on an area rather than an object within it. It is the practice the postwar rules on distinction and proportionality were written to prohibit, and treating raids like this one as collateral damage empties the term of meaning.
The rules that would govern such a raid today are set out in the page on rules of engagement, and the term people reach for instead is examined in the page on collateral damage.
The decision that made it possible
Until early 1945 the American bombing of Japan was high-altitude precision bombing aimed at factories, and it was not working well. Winds over Japan scattered bombs, cloud hid targets, and industrial production carried on.
The change was to abandon that approach. Aircraft would fly low, at night, stripped of much of their defensive armament to carry more bombs, and attack urban districts with incendiaries rather than aiming at individual plants.
It is worth being exact about what that meant. The reasoning included the fact that Japanese war production was dispersed into small workshops in residential districts, which made the districts themselves a target. The shift was from attacking things to attacking places, and everything about the March raid follows from it.
What the Tokyo raid shows that the atomic bombings obscure
That the threshold was crossed before the bomb. By March 1945 an air force could kill a hundred thousand civilians in a night, deliberately, using ordinary munitions, and the question of whether to do it had already been settled in practice.
That matters for how the atomic bombings are argued about. They are usually discussed as a unique moral decision. Read against this raid they look more like a continuation, with a more efficient weapon, of something already under way. Reading the index as a whole tends to produce that kind of correction, which is the reason for keeping the cases together.
Questions people ask about this
How many died in the Tokyo firebombing?
Was it deadlier than Hiroshima?
Why is it so little known?
Where this comes from
- Japan campaign — Wikipedia
- Tokyo vs. Hiroshima — Restricted Data, the nuclear secrecy blog
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