On the night of March 9-10, 1945, U.S. warplanes dropped incendiary bombs on eastern Tokyo, incinerating an estimated 100,000 civilians, injuring a million more and leaving a million homeless.

Leaving aside Hiroshima and Nagasaki, it is the single most deadly bombing raid in history — far surpassing the Dresden or Hamburg firestorms in the nightmarish annals of urban infernos, leaving behind a 41-sq.-km swath of smoldering ruins and grimly panoramic vistas where vibrant communities had been suddenly obliterated.

The commander of the firebombing campaign that systematically razed 67 Japanese cities was U.S. Air Force Gen. Curtis LeMay. He promoted the switch from conventional bombs to incendiaries and timed the Tokyo raid to coincide with windy weather, knowing the fires would spread more rapidly in the kindling of Tokyo’s wooden housing.

Firefighting capacity was so limited that authorities urged residents to dig their own air-raid shelters, with most being little more than foxholes covered by tatami mats soaked in water. Essentially, they were asking people to dig their own graves.

The firebombing was not solely a matter of damaging Japan’s factories and infrastructure.

This aerial terror was also vengeance, payback for Pearl Harbor and mistreatment of prisoners of war, and was intended to inflict maximum suffering on the populace. The line between military and civilian targets had been crossed well before this by both sides, but never on such a monstrous scale.

This “terror bombing” brought the war no closer to an end, though it did reduce war-related output and force the government to relocate production facilities to remote areas.

However, Japan’s military leaders were undaunted as they persisted in waging a war they knew they could not win. They were prepared to fight to the last dead Japanese civilian and were gambling on a great final battle in the hope that inflicting heavy casualties on invading American troops would improve the terms of surrender.

The Allies’ insistence on unconditional surrender raised worries about what would befall Emperor Hirohito, and military leaders were also mindful that they risked being held accountable for the horrors they inflicted throughout Asia unless they could secure a negotiated peace.

Prolonging the war meant there was a price to be paid and, as in most modern conflicts, civilians paid the highest price. The firebombing campaign left some 5 million people homeless throughout Japan, killing perhaps 500,000 civilians and wounding another 400,000 — excluding the Hiroshima and Nagasaki victims. LeMay also oversaw Operation Starvation, a strategy to mine Japan’s coastal waters and ports from the air, so disrupting shipping and the distribution of food. This supplemented a very effective submarine blockade.

Why are so few Americans aware of this grisly chapter of what U.S. historian John Dower has characterized as a race war waged without mercy?

Perhaps it’s because Allied war crimes were buried by the comforting narrative of the Good War (World War II) fought by the Greatest Generation that persisted long after it was discredited.

And which country, aside from Germany, has taken on board the full measure of its darkest chapters? Here, Japan and the U.S. share some common ground.

The ashes of more than 100,000 air-raid victims are interred at Yokoamicho Park in Sumida Ward, where there is a modest memorial. And in Koto Ward, documents and oral histories have been assembled at a private library/museum — but there is no publicly funded Tokyo Firebombing Museum or state memorial commensurate with the scale of this ghastly event.

In 1990, the Tokyo Metropolitan Government set up a committee to prepare plans for a memorial, but in his recent book “Tokyo Vernacular,” Jordan Sand, a professor at Georgetown University, states that “this was ultimately derailed by politicians on the right and the national bureaucracy.”

According to Sand, the firebombing of Tokyo has been swept under the national tatami mat because many in Japan held the Emperor responsible.

Yet bizarrely enough, on Dec. 7, 1964 — the 23^rd anniversary of Pearl Harbor — Emperor Showa awarded LeMay a highly prestigious Order of the Rising Sun, First Class — this, for a man who acknowledged that if the United States had been on the losing side, he would have been tried for war crimes.

Back in 2007, Prime Minister Shinzo Abe published an essay apologizing for Japan’s bombing of Chinese cities and civilians. He also suggested that the Japanese government, knowing defeat was inevitable, should have surrendered sooner, presumably to spare civilians the subsequent horrors inflicted throughout 1945, including the decimation of Tokyo, Hiroshima and Nagasaki.

More recently, in 2013 the Abe Cabinet declared that the Tokyo firebombing violated humanitarian principles of international law, although it was not illegal. Also in 2013, the Supreme Court rejected an appeal by plaintiffs who demanded an apology and compensation from the Japanese government for prolonging the war and subjecting them to the conflagration.

I asked three leading historians of Japan for their observations about the Tokyo firebombing.

Sven Saaler at Sophia University explained that the Tokyo blitz “always stood in the shadow of the nuclear bombs. Hiroshima and Nagasaki happened in August and were linked to the end of the war. Since the commemoration of World War II in Japan mostly is related to the end of the war and focused on the first half of August, the Tokyo bombing never played an important role in memory.”

Laura Hein from Northwestern University observed: “One of the things that makes it difficult to discuss indiscriminate firebombing of urban areas full of civilians on both sides of the Pacific is that all major combatants in World War II engaged in that practice. Anyone who wants to highlight the tragedy of one’s own side has to be prepared to acknowledge causing similar tragedy to others.”

She added that “destroying the enemy population’s morale is nearly always the only goal when the target is ordinary homes and small shops — and it very rarely works. It seems that people fight harder after their children or parents or friends die cruelly, rather than simply giving up.”

Yuki Tanaka, a researcher at the Hiroshima Peace Institute at Hiroshima City University — who coedited “Bombing Civilians” (2009) — noted that “the U.S. government has never expressed any sorrow or apology for the firebombings they conducted on Japanese cites. This is quite natural. It is because if they apologize for firebombings, they would have to apologize for the atomic bombings as well.” Indeed.

President Barack Obama won the Nobel Peace Prize for an April 2009 speech in Prague where he voiced support for nuclear disarmament. During his upcoming visit here, perhaps he can follow up by making an apology for the atomic bombings — one that many Japanese have been waiting a long time to hear.

Jeff Kingston