大山事件に関する外務省の対外発表（8月11日）
外務省情報部長が事件2日後の1937年8月11日に公表した事件の説明だが、当然日本には一切非がなかったという主張になっている。実際にはこれらの説明には矛盾も多く、信頼性には疑問符がつくのだが、これをそのまま鵜呑みにして大山事件を日中戦争正当化や対中国差別に用いる者が多い。
２３、大山事件に対する情報部長説明（8月11日）
1. The Chinese allege that Sub-Lieutenant Oyama tried to force his way into the Hungjao airdrome and, on being refused by the Chinese Peace Preservation Corps, drew his pistol, killing one of them. This is entirely untrue.
2. Sub-Lieutenant Oyama was on his way to the Headquarters of the Naval Landing Party from the western outpost (where one company of the marines is stationed) of which he was commander and whose duty it was to safeguard the lives and property of the Japanese in this district. There are in the western district Japanese-owned spinning factories such as the Toyoda-Boseki and Naigaimenka-Boseki*1. It was quite proper for him to make the necessary inspection of the neighbourhood of the Monument Road where at about 6 p.m. he was shot dead, together with First-class Seaman Saito who was driving the officer's car. Both were in full naval uniform. From the fact that Sub-Lieutenant Oyama did not carry his revolver with him (revolver was later found with his personal belongings at the Headquaters) it is perfectly clear that he was not in a position to pick any quarrel with the Chinese troops. Nor is it likely that he was so reckless as to force his way into the airdrome which was heavily guarded by the Chinese armed with machine-guns. Although it is true that Saito had his revolver with him, it is clear that he could not make use of it as he was at the wheel of the car. Moreover, Sub-Lieutenant Oyama could not have used Saito's revolver because of the distance separating the seats of the two in the car. It is very evident, therefore, that both Oyama and Saito were murdered by the Chinese troop without the least provocation on their part.
大山中尉が租界西部の日本の紡績工場の警備担当であり、そこから陸戦隊本部に帰るためにモニュメント路(碑坊路)（現・綏寧路）を通ったと書いているが、地図上から考えればこれはまずありえない。文中に挙げている豊田紡績も内外綿紡績も確かに租界西部に工場があるが、モニュメント路(碑坊路)（現・綏寧路）より数キロ東にある。豊田紡績や内外綿花紡績から北四川路に戻るのなら、モニュメント路(碑坊路)（現・綏寧路）を通ることは明らかに遠回りになり、ありえない。
3. The motor-car was discovered off the main road, at about 300 meters from the gate of the airdrome, with more than 50 marks of small-calibre bullets as well as several larger with blood and Oyama was found lying dead outside the car. Chinese troops were massed in the vicinity.
別の記事では事件現場は正門から北へ約100メートルとあるが、ここでは300メートルとされている。この外務省発表以外に300メートル説を伝える記事は見当たらない。
4. A formal joint inquiry held on the 10th established the fact that both Oyama and Saito were murdered by the Chinese immediately after fire was concentrated upon them, the first bullets which pierced their faces proving fatal. Oyama received, however, more than 18 wounds by bayonets and swords. Apparently the Chinese hit his head with the butts of their rifles and dragged him from the car after which they thrust fixed bayonets into his body. Part of his intestines was laid bare and a hole large enough to pass a fist through was dug into his heart. Saito was also killed outright by the first shot but was later subjected to similar unspeakable atrocities. It is said that the Chinese used dum-dum bullets. Both men were completely robbed of their possessions, including sword, shoes and wrist watches a conduct most unbecoming of soldiers in a regular army. When Japanese and Chinese troops face each other and untoward incidents happen, chances are that they are always perpetrated by these ill-disciplined Chinese soldiery.
5. In order to avoid the extension of fighting to Central and South China, the Japanese Government have been taking a most cautious and peaceful attitude in Shanghai. But the Chinese have established strong positions around the Japanese Concession menacing its safety. Moreover, they have been inciting anti-Japanese sentiment of the mass so that Japanese residents, women as well as children of tender ager, have been subjected ti various molestations. Now the Japanese are not able to purchase even their daily provisions.
日本政府は華中華南への戦火の波及を避けるために上海では慎重・平和的な態度をとっていたと主張しているが、だとすれば、大山中尉による虹橋飛行場の偵察は政府の意図に反した行為といわざるを得ない。
中国側も緊張していることは容易に理解できる状況で、中国空軍専用の飛行場を偵察に行くのはいくら何でも挑発以外の何ものでもなく、軽率な行為と言える。
あるいはそれを狙っていたのかもしれない*2。
6. It is said that the policing of Monument Road which is an Extra-Settlement road has been illegally taken over by the Chinese. It is still a pending issue. However, if the Chinese have assumed the right to police the section under discussion it is clear that they should assume full responsibility for the maintenance of peace and order there. If they are merely illegally occupying the said section, it must be said that the Chinese are seriously interfering with the peace and order of that locality which gravely concerns the welfare of the foreign, and particularly, Japanese residents in Shanghai.
7. Since both Sub-Lieutenant Oyama and Seaman Saito were on their duty, they are entitled, by law, to the right of extraterritoriality.
