The 2004 Chuetsu earthquake and the koi industry
Key facts: The 2004 Chūetsu earthquake (中越地震, Chūetsu jishin) struck Niigata Prefecture on October 23, 2004, devastating Yamakoshi, a village long associated with nishikigoi breeding, and disrupting Japan's koi production region.[1][2]
The Chūetsu earthquake occurred at 17:56 JST on October 23, 2004, with the Japan Meteorological Agency recording a magnitude of 6.8 and a maximum intensity of Shindo 7 at Kawaguchi, Niigata.[1] At least 68 people were killed and more than 131,600 houses were damaged across four prefectures, with economic losses estimated at US$40 billion, making it at the time the second costliest natural disaster on record.[1]Among the hardest-hit communities was Yamakoshi (山古志村, Yamakoshi-mura), a village in Niigata's Koshi District whose main industry was raising carp supplied to ponds and lakes throughout Japan.[1][3] The quake caused landslides, destroyed roads, and forced the entire village to evacuate.[2]The earthquake and Yamakoshi
The mainshock struck on the Muikamachi fault and was followed by further strong aftershocks, including events reaching Shindo 6+ at Ojiya and Kawaguchi within the same evening.[1] The earthquake triggered at least 442 documented landslides in Niigata Prefecture, and in the Imo River basin near Yamakoshi, multiple landslide dams formed, raising fears of flooding and prompting the evacuation of 439 people from 101 households.[1]In Yamakoshi itself, the village seismometer at the village office was destroyed by the shaking, so the exact local intensity is unknown, but the landscape was severely altered by slope failures, and all roads into the village were cut off.[2] The entire population was placed under evacuation orders, and by October 26 residents had relocated to shelters, mostly temporary housing in neighboring Nagaoka.[2] At least five deaths related to the earthquake occurred in Yamakoshi.[1]The evacuation order was not mostly lifted until April 1, 2007, and many households that relocated outside the village during the disaster did not return, contributing to long-term population decline and an aging community.[2] On April 1, 2005, Yamakoshi was merged into the expanded city of Nagaoka along with several other municipalities.[3][2]Impact on koi breeders
Yamakoshi's carp-raising industry, including nishikigoi breeding ponds, was disrupted by the earthquake, and residents feared permanent consequences for their livelihoods.[1] A Japanese-language news report from the Japanese Communist Party's newspaper Akahata described koi breeders in the Yamakoshi area losing fish as ponds and breeding facilities (yoshokuike) were damaged, with some farmers reporting the loss of carp valued at tens of millions of yen as breeding ponds and reservoirs failed.[5]According to the report, breeders in the affected hamlets struggled with road damage that cut off access to feeding and maintaining the fish, and some ponds lost water entirely due to cracks and landslides affecting reservoirs that fed the breeding ponds.[5] Economic damage to the wider agricultural and breeding community in the disaster zone was described as substantial, compounding the human toll of displacement and evacuation across the Chūetsu region.[5][1]The helicopter rescue of livestock
With roads into Yamakoshi severed by landslides, residents had to leave behind livestock, including around 1,000 cattle, when they evacuated.[1] To save his business, one cattle owner in Yamakoshi began airlifting 700 cattle out of the village by helicopter starting November 2, 2004, at considerable expense.[1]On November 6, 2004, the Emperor and Empress inspected the disaster area from the air and visited evacuees in shelters.[2] The episode of isolated villages needing aerial evacuation and supply became one of the defining images of the disaster's impact on Yamakoshi, whose roads remained impassable for an extended period after the quake.[1][2]Industry response and recovery
The All Japan Nishikigoi Promotion Association (全日本錦鯉振興会), whose Koi Promotion Center is located in Ojiya in the heart of the affected region, records that the Chūetsu earthquake caused the Niigata koi production area to suffer serious damage.[4] The organization's own timeline notes that earlier in 2004 its 36th All Japan Nishikigoi Show had already been canceled due to a koi herpesvirus outbreak, meaning the breeding region faced both a disease crisis and a major earthquake within the same year.[4]Despite the damage, the association continued its activities in subsequent years, including placing koi in the Kyoto State Guest House in April 2005 and holding further All Japan Nishikigoi Shows, with the 41st show held in Niigata itself in 2010.[4] The association's history also shows that Niigata's koi industry faced later disruptions, such as the cancellation of the 29th All Japan Young Koi Show after the 2011 East Japan earthquake, indicating a recurring vulnerability of the Niigata breeding region to seismic events.[4]Long-term effects on the region
Niigata Prefecture as a whole recorded the Chūetsu earthquake as a major regional event, with Shindo 6+ measured at Ojiya in the Chūetsu area, one of the prefecture's four geographical divisions.[6] Yamakoshi's population, already declining before the disaster due to broader demographic trends, continued to fall afterward, and the proportion of residents aged 65 or older in the area rose sharply between 1980 and 2015, with the earthquake cited as one contributing factor rather than the sole cause of depopulation.[2]The village's merger into Nagaoka, which had already been agreed before the earthquake, proceeded on April 1, 2005, with the former village area retained under the name "Yamakoshi" rather than being folded into a generic designation, reportedly partly in recognition of its identity following the disaster.[2] Nishikigoi breeding has continued to be identified with the Yamakoshi area as part of its historical association with the origin of the practice.[2]Common questions
When did the Chūetsu earthquake happen?
It struck Niigata Prefecture at 17:56 JST on October 23, 2004, with the Japan Meteorological Agency recording a magnitude of 6.8.[1]
Why was Yamakoshi significant to the koi industry?
Were koi breeding ponds damaged in the earthquake?
According to a Japanese-language news report, koi breeders in the Yamakoshi area lost fish and suffered damage to breeding ponds and reservoirs, with some farmers reporting substantial losses.[5]
What happened to Yamakoshi's livestock during the disaster?
With roads cut off, residents had to leave behind about 1,000 cattle; one owner began airlifting 700 cattle out of the village by helicopter starting November 2, 2004.[1]
Did the earthquake affect the broader Niigata koi industry?
The All Japan Nishikigoi Promotion Association states that the koi production area suffered serious damage from the earthquake, coming in the same year as a koi herpesvirus outbreak that had already forced cancellation of its 36th All Japan Nishikigoi Show.[4]
Related koi topics
References
- ^ 2004 Chūetsu earthquake (Wikipedia). Wikipedia. en.wikipedia.org/wiki/2004_Chūetsu_earthquake. Retrieved November 2026.
- ^ 山古志村 (Wikipedia). Wikipedia (Japanese). ja.wikipedia.org/wiki/山古志村. Retrieved November 2026.
- ^ Yamakoshi, Niigata (Wikipedia). Wikipedia. en.wikipedia.org/wiki/Yamakoshi,_Niigata. Retrieved November 2026.
- ^ History of the All Japan Nishikigoi Promotion Association - All Japan Nishikigoi Promotion Association. All Japan Nishikigoi Promotion Association. jnpa.info/en/about/history/. Retrieved November 2026.
- ^ Вn͂܁@Vznk/r͒炪ATŐ/ꖇ̂ɐ\~/x߂jVLSCYn. jcp.or.jp. jcp.or.jp/akahata/aik3/2004-11-27/15_01.html. Retrieved November 2026.
- ^ Niigata Prefecture (Wikipedia). Wikipedia. en.wikipedia.org/wiki/Niigata_Prefecture. Retrieved November 2026.