Japanese Prime Minister Shinzo Abe lays a wreath during the 70th anniversary ceremony of the atomic bombing of Hiroshima at the Hiroshima Peace Memorial Park on Aug. 6. (Chris McGrath/Getty Images)

TOKYO — This Saturday marks the 70th anniversary of Japan’s surrender at the end of World War II, a period during which Japan’s Imperial Army committed brutal acts that led to its leaders being tried for war crimes and crimes against humanity.

Prime Minister Shinzo Abe will deliver a statement on Friday to mark the anniversary, and Emperor Akihito will make his own remarks on Saturday.

The indictment at the International Military Tribunal for the Far East – more commonly known as the Tokyo war crimes trials – accused Japanese military leaders of perpetrating “mass murder, rape, pillage, brigandage, torture and other barbaric cruelties upon the helpless civilian population of the over-run countries."

They were also found guilty of “murdering, maiming and ill-treating prisoners of war [and] civilian internees,” and forcing them to labor “under inhumane conditions.”

The worst incidents of the war involved the murder, raping, looting, and burning in the Chinese city of Nanjing (then known as Nanking) in 1937.

“At least twenty thousand Chinese women were raped in Nanjing during the first four weeks of the Japanese occupation, and many were mutilated and killed when the Japanese troops were finished with them,” historian James Bowen writes on the Pacific War Historical Society Web site. “The Japanese troops were encouraged by their officers to invent ever more horrible ways to slaughter the Chinese population of the city.”

The judges at the Tokyo war crimes trials accepted that at least 200,000 Chinese civilians and prisoners of war were slaughtered in the six weeks after Nanjing fell to the Japanese. Some historians say the true number reached 370,000.

There was also the Bataan death march, in which about 78,000 sick and starving prisoners of war — 12,000 Americans and 66,000 Filipinos, according to "Bataan: The March of Death" by Stanley Falk, former Air Force chief historian — were forced to walk 66 miles in the Philippines in April 1942. The U.S. Army Center of Military History estimates that 600 Americans and 10,000 Filipino prisoners were killed by the Japanese guards during the march.

Then there are the horrific activities of "Unit 731," which conducted experiments on people while they were still alive.

“Deliberately infected with plague, anthrax, cholera and other pathogens, an estimated 3,000 of enemy soldiers and civilians were used as guinea pigs,” says the 731.org Web site devoted to the unit’s activities. “Some of the more horrific experiments included vivisection without anesthesia and pressure chambers to see how much a human could take before his eyes popped out.”

So when Emperor Hirohito surrendered on Aug. 15, 1945, Japan had plenty to be sorry about. Still, these incidents, accepted as fact outside Japan, have been questioned by some here. Some historians and Japanese nationalists say Japan’s war crimes have been overstated, while others contend that Japan has apologized enough and should be allowed to move on.

Prime ministers over the years have voiced remorse for Japan’s wartime actions, including Nobusuke Kishi, grandfather of current prime minister Abe, who voiced “deep regret” in Burma in 1957 and expressed “our heartfelt sorrow” in Australia. (However, he was a nationalist aiming to restore Japan’s military might.)

When Japan and South Korea normalized diplomatic relations in 1965, foreign minister Shiina Etsusaburo said Japan was “deeply remorseful" for the “unfortunate times” in the countries’ histories.

A big part of the problem stems from the fact that Japan’s official apologies have been partially undone by remarks — like when then-justice minister Shigeto Nagato said in 1994 that the Nanjing massacre "was fabricated” (he resigned) and more recently Abe's government last year asked a United Nations special rapporteur to revise a 1996 report on wartime “comfort women” (she refused).

“The world criticizes Japan for failing to come to terms with its past,” writes Jennifer Lind of Dartmouth College in her book  "Sorry States: Apologies in International Politics."

“Tokyo’s apologies have been perceived as too little, too late. Even worse, its politicians repeatedly shock survivors and the global community by denying past atrocities; its history textbooks whitewash its wartime crimes," Lind writes. "Japan sees itself as a pacifist, cooperative, and generous global citizens, with a strong antiwar and antinuclear identity. But after sixty years, Japan’s neighbors still see bayoneted babies. Relations between Japan and its former victims remain fraught with distrust.”

Here are the official apologies that Japan has made.

The "Jewel Voice Broadcast"

This wasn't an actual apology – in fact, if there was anything apologetic in the document, it was an apology to the Japanese people for admitting defeat – but it paved the way for future apologies.

In a radio address that was broadcast at noon on Aug. 15, 1945, just days after the atomic bombings of Hiroshima and Nagasaki, Emperor Hirohito read out a document officially known as the Imperial Rescript on the Termination of the War.

It was the first time the people of Japan had ever heard their emperor’s voice, and his language was classical and difficult for ordinary Japanese to understand.

He never used the word “surrender,” but the emperor said that he accepted the terms of the Potsdam Declaration, the ultimatum from the Allies that gave Japan a choice: surrender, or face "prompt and utter destruction.”

Read the full text here.

1993 – Kono statement 

This statement, by Yohei Kono, the chief cabinet secretary at the time, came after a government study into the use of sex slaves during World War II. Mainstream historians say that about 200,000 women, mainly from Korea and China, were forced to work in military brothels, euphemistically called “comfort stations,” during the war.

In his statement, Kono said that the Japanese military was “directly or indirectly, involved in the establishment and management of the comfort stations and the transfer of comfort women” and that in many cases they were recruited against their own will. “They lived in misery at comfort stations under a coercive atmosphere,” the statement said.

“Undeniably, this was an act, with the involvement of the military authorities of the day, that severely injured the honor and dignity of many women. The Government of Japan would like to take this opportunity once again to extend its sincere apologies and remorse to all those, irrespective of place of origin, who suffered immeasurable pain and incurable physical and psychological wounds as comfort women.”

A number of Japanese scholars – like Ikuhiko Hata, an emeritus professor at Nihon University, who is being promoted by the current government as a reliable expert – say that the numbers are grossly exaggerated and the women were nothing more than prostitutes.

Abe caused consternation last year when he ordered a review of the Kono statement, after some in his government said they could not guarantee the report’s veracity. The review was conducted – eliciting strong protests from South Korea in particular – but in the end, Abe’s government upheld the 1993 statement.

1995 – Murayama statement

This landmark statement, made by the Socialist prime minister Tomiichi Murayama on the 50th anniversary of the war’s end, is widely considered the Japanese government’s official apology for its actions in the first half of 20th century.

It is unequivocal:

During a certain period in the not too distant past, Japan, following a mistaken national policy, advanced along the road to war, only to ensnare the Japanese people in a fateful crisis, and, through its colonial rule and aggression, caused tremendous damage and suffering to the people of many countries, particularly to those of Asian nations. In the hope that no such mistake be made in the future, I regard, in a spirit of humility, these irrefutable facts of history, and express here once again my feelings of deep remorse and state my heartfelt apology. Allow me also to express my feelings of profound mourning for all victims, both at home and abroad, of that history.

2005 – Koizumi statement

On the 60th anniversary, Prime Minister Junichiro Koizumi upheld the Murayama statement, repeating the key words.

In the past, Japan, through its colonial rule and aggression, caused tremendous damage and suffering to the people of many countries, particularly to those of Asian nations. Sincerely facing these facts of history, I once again express my feelings of deep remorse and heartfelt apology, and also express the feelings of mourning for all victims, both at home and abroad, in the war. I am determined not to allow the lessons of that horrible war to erode, and to contribute to the peace and prosperity of the world without ever again waging a war.

2015 – Abe statement

Abe will hold a cabinet meeting at 5pm local time on Friday to seek approval for his statement. That approval needs to be unanimous, but indications are that it will be. He will then hold a press conference at 6pm local time to read out his statement.

What will Abe say? South Korea and China want him to repeat the words “colonial rule and aggression” at a minimum, and apologize again. Recent reports say that Abe will indeed apologize. But don’t expect that to be the end of it. Even if he offers a “heartfelt apology” like Murayama and Koizumi — not just “deep remorse” as he has done previously — Japan's neighbors are unlikely to be satisfied.

In Asia, all eyes will be on Abe on Friday.

Correction: This post has been updated to correct the numbers of Americans and Filipinos killed during the Bataan death march.