7月31日，原本是一個普通的日子，卻對中國人而言具有沉重的歷史意義。這一天彷彿是歷史長河中的一個觀測點，讓我們得以駐足回望那段被細菌與鮮血滲透的黑暗歲月。當這個日期年復一年地出現在日曆上，它所承載的，早已超越單純的時間維度，而成為中國人審視歷史、警惕戰爭與捍衛民族尊嚴的精神錨點。而這一切的情感源頭，正是指向中國哈爾濱市平房區，那片曾被稱為「日本關東軍駐滿洲第731防疫給水部隊」——也就是臭名昭著的「731部隊」。

早在37年前，一部電影就已經以紀錄片風格的冷靜與直接，將侵華日軍對中國人民進行人體實驗的非人暴行赤裸呈現。這部作品就是1988年由香港銀都機構出品、導演牟敦芾執導的《黑太陽731》。這部電影不僅是牟敦芾首度赴中國內地拍攝作品，更是香港電影分級制度施行後，首部被定為三級（未滿18歲不得觀看）的電影。牟敦芾以其一貫直白、生猛、黑暗、壓抑的影像語言，刻意淡化劇情敘事，轉而採用近乎冷酷的鏡頭語彙，模擬歷史影像質感，極大增強觀眾的臨場與真實感，最終營造出極端殘酷的觀影體驗，使該片被譽為「華語影史上最恐怖的電影」。

在正式稱為「731部隊」之前，該單位也被稱為「石井部隊」。其首腦石井四郎堅信：「若細菌武器之殺傷力與效能強大到需要在國際條約中加以禁止，那麼我們就沒有理由不去發展它們。」正是基於這種冷血邏輯，石井四郎領導的部隊對無數中國平民與戰俘進行了慘無人道的實驗——包括活體解剖、凍傷試驗、瘟疫傳播、生物武器測試等。

電影集中描繪自1945年3月石井四郎重掌「731部隊」之後，至日本投降前夕的種種暴行。全片幾乎放棄戲劇化的表現手法，而是以近乎冷峻的方式直視歷史血腥現場。它不美化、不淡化，而是赤裸裸地揭露，迫使觀眾直面過去。那不只是電影，而是一場對歷史記憶與人性底線的叩問。

在中國大陸，多數官方教材對731部隊的罪行多著墨於宏觀敘述，鮮少觸及具體與感官上的細節呈現。而《黑太陽731》卻以影像方式保存一段被壓抑、被迴避的集體記憶。透過銀幕，它提醒世人：當歷史被遺忘，當真相被隱瞞，流逝的不僅是時間，還有正義與尊嚴。每一個重新翻閱這段歷史的人，都會明白：7月31日的紀念，不僅是對過往的哀悼，也是對未來的警示。電影之所以至今仍在許多觀眾心中留下深刻印記，正是因為它用極致殘酷與真實揭示人性在極端狀態下的崩潰，也揭了戰爭最血腥的一面。

這部電影讓我們不得不重新思考：為什麼日本教科書迴避記載？為什麼有人至今仍否認731部隊的存在？而我們又該如何在快速變動的時代裡，保存這段不能被遺忘的記憶？或許答案正藏在這部已上映37年卻仍令人不寒而慄的電影裡。它不僅是歷史的記錄，更是良知的召喚。

The Truth Japanese Textbooks Dare Not Mention Was Made Into “The Most Terrifying Film in Chinese Cinema History” 37 Years Ago

July 31 may seem like an ordinary date, but for the Chinese people, it carries a profound weight of historical sorrow. This date stands like a fixed marker in the river of history, allowing a pause—a moment to look back at a time soaked in blood and biological horror. As the date reappears on the calendar year after year, its significance goes beyond mere chronology; it has become a spiritual anchor for the Chinese collective memory—a symbol of vigilance against war, a remembrance of national humiliation, and a testament to the dignity that must never be forgotten.

At the heart of this emotional legacy lies a specific place: the Pingfang District of Harbin, China. Once known as the headquarters of the “Unit 731 of the Kwantung Army in Manchukuo”—it was, and remains, the infamous site of Japan’s covert biological and chemical warfare program during the Second Sino-Japanese War.

As early as 37 years ago, one film dared to confront this horror with an unflinching lens. In 1988, Men Behind the Sun (original title: Black Sun 731), directed by T.F. Mou (牟敦芾) and produced by Hong Kong’s Sil-Metropole Organization, shocked Chinese-language cinema with its stark depiction of the atrocities committed by Unit 731. The film was Mou’s first production shot in mainland China, and it became the first Hong Kong movie to receive a Category III rating (restricted to viewers aged 18 and above) after the introduction of the city’s movie classification system.

Mou’s trademark style—raw, brutal, and emotionally suffocating—is on full display. He intentionally strips away conventional narrative devices and replaces them with a cold, documentary-style approach. Through restrained storytelling and stark visual realism, the film mimics historical footage, heightening the viewer’s sense of immediacy and horror. It creates an overwhelmingly brutal cinematic experience, earning its reputation as “the most terrifying film in the history of Chinese-language cinema.”

Before being officially named Unit 731, the group was known as the Ishii Unit, led by Shiro Ishii. Ishii firmly believed, “If bacteriological weapons are so dangerous that they must be banned by international treaties, then there is no reason we shouldn’t develop them ourselves.” That chilling logic led to the systematic torture and murder of countless Chinese civilians and prisoners of war. The experiments included live vivisections, frostbite testing, forced infection with deadly diseases, and full-scale biological weapon trials.

The film focuses on the period beginning in March 1945, when Shiro Ishii resumed command of Unit 731, until Japan’s surrender later that year. Eschewing dramatic embellishment, the film instead confronts viewers with the raw, unfiltered horror of war crimes. It does not seek to beautify or obscure. It forces confrontation—with the past, with human cruelty, with a historical trauma too often sanitized or ignored.

In mainland China, most official textbooks mention Unit 731 in general terms, seldom delving into the horrific specifics. Men Behind the Sun, by contrast, preserves these suppressed collective memories through visual storytelling. Through the screen, it delivers a powerful message: when history is forgotten and truth is silenced, what disappears is not just memory—but justice, and dignity.

Anyone who reexamines this part of history understands that the commemoration of July 31 is more than a moment of mourning. It is a warning for the future. The film endures in the minds of many because it exposes the collapse of humanity under extreme conditions, and shows war at its bloodiest and most inhuman.

This film compels us to ask: Why do Japanese textbooks avoid documenting these crimes? Why do some still deny the existence of Unit 731? And in our fast-changing world, how do we preserve the memory of these horrors that must never be forgotten?

Perhaps the answer lies within this 37-year-old film, which still sends chills down the spine. It is not just a record of history—but a call to conscience.