| native_name= SOS遭難事件
| native_name_lang = ja
|duration=10 July 1984 —– 28 February 1990
|Location=[[Mount Asahidake]], [[Daisetsuzan National Park]], [[Hokkaidō]], [[Japan]]
|type=[[Missing person|Disappearances]], [[List of unsolved deaths|unsolved deaths]], unexplained occurrences
|cause=Unknown
|outcome=[[Cold case]]
|reported deaths=At least 1
*Two missing hikers rescued}}
The '''SOS incident''' occurred in [[Mount Asahidake]] in [[Daisetsuzan National Park]] in Japan in 1989. Two lost mountaineers were located and rescued after search teams spotted a large [[SOS]] message built from fallen birch logs, but the mountaineers had not created this message, which was determined to have been in place since at least 1987. After returning to search the area for more missing people the next day, police found [[Human skeleton|skeletal remains]] in the vicinity (initially determined to belong to a female in the area,) in addition to personal belongings —of a presumed-male hiker found stuffed into a tree root not far from the sign. The items includingincluded an ID (belonging to Kenji Iwamura, a man who had been missing since 1984), 2 cameras, a notebook, and a tape recorder with tapes featuring a distressed man calling for help — of a presumed-male hiker found stuffed into a tree root not far from the sign. It is still not known who constructed itthe sign.
== Background ==
On the afternoon of 24 July 1989, on the path from Mount Kurodake to Mount Asahidake of Daisetsuzan National Park, two [[Tokyo]] men were lost after mountaineering. While going through the climbing route, they deviated down Mount Asahidake, south towards the ChubetsugawaChubetsu river. The Hokkaido police searched in a helicopter and ended up finding a giant SOS sign made of 19 [[birch tree]]s, each roughly 5 meters long. It was built by stacking cut downfelled birch trees. The two missing people were soon safely rescued 2–3 km north from the sign.<ref name="asahi_1989-07-26">{{cite news|title=北の山中 届かなかった・SOS 近くに白骨、遭難か 北海道・旭岳 |newspaper=朝日新聞 |date=1989-07-26}}</ref><ref name="mainichi_1989-07-26">{{cite news|title=「SOS」木文字 近くに白骨散乱 大雪山系の湿原 遭難者か |newspaper=毎日新聞 |date=1989-07-26}}</ref><ref name="yomiuri_1989-07-26">{{cite news|title=大雪山系 「SOS」文字 そばに人骨 遭難者か、倒木を並べる |newspaper=読売新聞 |date=1989-07-26}}</ref><ref name="nippon-kakomon">{{cite web|title=過去の放送内容 【第84回】「山の上の巨大構造物"SOS遭難事件"の真相とは?」(3月1日放送) |work=[[上田晋也のニッポンの過去問]] |url=https://www.tbs.co.jp/nippon-kakomon/20170301.html |publisher=TBSテレビ|accessdate=2021-10-02|archiveurl=https://web.archive.org/web/20200921135435/http://www.tbs.co.jp/nippon-kakomon/20170301.html |archivedate=2020-09-21}}</ref>
The Hokkaido police believed that the SOS letters made of wood werehad alsobeen madeconstructed by the two people that they had rescued. However, when the police briefeddebriefed the two people about the situation after the rescue, they did not know anything about the SOS sign. The Hokkaido police, who thought that there was another victim, dispatched a helicopter again on the following day and searched the surrounding area. The police discovered fragments of [[Human skeleton|human bones]] with traces of animal bites. andIt appeared that some bonesof werethe broken,bones possiblyhad whilebeen thefractured personprior wasto alivedeath. In a separate area near the SOS sign, the police discovered a hole just large enough to fit a single human, which included four [[cassette tape]]s, a [[tape recorder]], a [[backpack]], some [[amulet]]s, a [[skull|human skull]], a [[tripod]], a pair of men's [[Sneakers|basketball shoes]], two [[camera]]s, a [[notebook]], and the [[driver's license]] of Kenji Iwamura, a 25-year-old male office worker from [[Kōnan, Aichi|Kōnan]], [[Aichi Prefecture]] who had gone [[Missing person|missing]] on 10 July 1984 after he set out hiking to Asahidake. When Iwamura failed to appear for work a week later, his parents asked police to search for him, but they found no trace.<ref name="asahi_1989-07-26" /><ref name="mainichi_1989-07-26" /><ref name="yomiuri_1989-07-26" /><ref name="nippon-kakomon" /> ToAs dateof {{currentyear}}, Iwamura has been missing for {{age|1984|7|10}} years, and ispolice believed bythat authoritieshe to beis deceased.{{cn|date=September 2024}}
The human bones were sent to [[Asahikawa Medical University]] and were identified initially ofas those of a woman aged 20–40 years. On 27 July, the police decided to play the recordings on the cassette tapes. On one of the recordings, the voice of a young man is heard shouting for 2 minutes and 17 seconds. A translation of the man shouting on the recording is as follows:<ref name="asahi_1989-07-28">{{cite news|title=大雪山遭難 テープ再生 叫び悲痛 2分17秒 |newspaper=朝日新聞 |date=1989-07-28}}</ref><ref name="nippon-kakomon" />
{{quotation|SOS, help me, I can't move on the cliff, SOS, help me.<br />
The place is where I first met the helicopter. The [[Sasa (plant)|sasa]] [a type of bamboo plant] is deep and you can't go up. Lift me up from here.}}
The rest of the tapes included music from the anime TV shows, ''[[Super Dimension Fortress Macross|Macross]]'' and ''[[Magical Princess Minky Momo]]''. In addition, a cutout of artwork of "Magical Princess Minky Momo" was used as a case for the cassette tape. In regards to the SOS sign, the [[Ministry of Agriculture, Forestry and Fisheries (Japan)|Japan Forestry Agency]] and the [[Geospatial Information Authority of Japan|Japan Geographical Authority]] took a look at previous topographic map data used to find aerial photographs, in which it was confirmed that the SOS sign was reflected in the images taken on 20 September 1987.<ref name="mainichi_1989-07-28" /><ref name="asahi_1989-07-29">{{cite news|title=「SOS」ナゾなお深く 女性の骨 男性の靴 結ぶ"線"浮かばず |newspaper=朝日新聞 |date=1989-07-29}}</ref><ref name="mushi">{{cite web|title=虫ん坊 2018年6月号(195 手塚マンガあの日あの時 あんなネタこんなネタ、小ネタコレクション!! |url=https://tezukaosamu.net/jp/mushi/201806/column.html |author=[[黒沢哲哉]] |work=手塚治虫公式サイト |publisher=株式会社手塚プロダクション |accessdate=2021-10-02 |archiveurl=https://web.archive.org/web/20180606052824/http://tezukaosamu.net/jp/mushi/201806/column.html |archivedate=2018-06-06}}</ref><ref name="asahi_1989-07-28" />
An acquaintance of Iwamura gave testimony that Iwamura had been carrying a recording of theme songs on a tape, as well as the same size of basketball shoes that were discovered in the recent search. On the other hand, since the human skeleton was initially identified as a female, it was thought by investigators that there were two men and a woman that had gone missing at the park. However, there was no record of the missing female in Asahidake and Iwamura was said to have gone alone into the mountain. The identity of the woman and the potential relationship to Iwamura was unknown and caused confusion in the investigation and media coverage.<ref name="asahi_1989-07-29" /><ref name="asahi_1989-07-26" /><ref name="yomiuri_1989-07-26" /><ref name="apnews.com">{{Cite news|date=July 30, 1989|title=Driver's License Found Near SOS on Mountain Slope|url=https://apnews.com/article/58a71324ae12619492ea7e98b089a785}}</ref>
The Asahikawa East police station announced on 28 February 1990 that after a reexamination of all the human bones that were found, they now believed that the skeleton was actually male, not female, and that they believed the skeleton was actually that of one man.<ref>{{cite news|title=愛知の男性と断定 「SOS」の人骨 |newspaper=朝日新聞(夕刊) |date=1990-03-01}}</ref>
== Aspects of the case ==
[[File:旭岳直下の金庫岩.jpg|link=https://ja.wikipedia.org/wiki/%E3%83%95%E3%82%A1%E3%82%A4%E3%83%AB:%E6%97%AD%E5%B2%B3%E7%9B%B4%E4%B8%8B%E3%81%AE%E9%87%91%E5%BA%AB%E5%B2%A9.jpg|right|thumb|Safe Rock]]
=== Cause of the incident ===
There is a large rock nicknamed the "Safe Rock" on the ridge of Mount Asahidake, which is used as a guidepost. However, there is also a similar large rock nicknamed the "Fake Safe Rock" near the Safe Rock, and if youone were to accidentally fall from the Fake Safe Rock, youthey would willbe reachin the area where the SOS incident occurred. The slope above the main area is a dense [[Sasa (plant)|Sasasasa]] grove that grows sideways,. and itIt is easy to enter the bottom from the top, but it is difficult to climb from the bottom to the top,. thereThere is a cliff where the incident occurred. The terrain is difficult to escape.; This was supported by thein fact that, a few days after the incident was discovered, a news media interview team who visited the site was unable to escape from the area and washad to be rescued.<ref>{{cite web|title=遭難事故の多い旭岳。なぜ?どこで?実際の事故原因から学ぶ対策方法 |url=https://yamahack.com/2842 |author=高橋典子 |work=YAMA HACK |publisher=スペースキー |date=2020-09-12 |accessdate=2021-10-02 |archiveurl=https://web.archive.org/web/20210302010754/https://yamahack.com/2842 |archivedate=2021-03-02}}</ref><ref name="mainichi_1989-07-28">{{cite news|title=「SOS」周辺の捜索打ち切り |newspaper=毎日新聞(夕刊) |date=1989-07-28}}</ref>
=== The SOS sign ===
The wooden letters of the SOS sign were made by stacking large fallen birch trees, and it was estimated that it took about two days and considerable effort to create such a giant sign. It was speculated that the sign was made by the missing person that the skeleton belonged to, but in the autopsy of the skeleton that was found, who investigators believed was Iwamura, the body was described as thin and weak andto the point that it would have been impossible for him to make the sign on his own. No [[axe]] that wouldcould have been used to cut trees down to make the sign has been found. AnSome observation by some that has beenhave pointed out is that [[Osamu Tezuka]]'s ''[[Astro Boy]]'' has a scene in which fallen trees are arranged in the shape of SOS.<ref name="mushi" /><ref name="tanteifile">{{cite web|author=[[山口敏太郎]]|date=2010-04-18|title=謎のテープレコーダー 大雪山SOS事件とは|url=http://www.tanteifile.com/onryo/kaiki/2010/04/18_01/body.html|publisher=探偵ファイル~山口敏太郎の怪奇探偵~|accessdate=2021-10-02|archiveurl=https://archive.phtoday/VNGIk20130428035153/http://www.tanteifile.com/onryo/kaiki/2010/04/18_01/body.html|archivedate=2013-04-28}}</ref><ref name="asahi_1989-07-28" />
=== SOS tape recording ===
The reason for the recordingpurpose of the SOS tape recording is unknown, but it is speculated that the man on the recording, who was stuck, recorded it so that the search team could hear it before he became debilitated and unable to speak. It is speculatedalso possible that it was accidentally switched on and recorded while the man was yelling for help. Many have speculated that the man yelling was Iwamura, but when Iwamura's parents were asked about the recording, they said they could not confirm that the manvoice on the recording was their son's.<ref name="apnews.com"/><ref name="mushi" /><ref name="tanteifile" />
==See also==
[[Category:Unsolved deaths]]
[[Category:1989 disasters in Japan]]
[[Category:July 1989 events in AsiaJapan]]
[[Category:History of Hokkaido]]
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