Three arrested in Chiba over unauthorized embankment tied to Typhoon 25 landslide
In short
Chiba Prefectural Police arrested three men on Oct. 7 on suspicion of violating the prefecture's residual soil ordinance over an unauthorized embankment on private land in Ichihara City. The site covered about 10,000 square meters and the embankment stood up to about 15 meters high, reports said. The company involved had received administrative guidance over another unauthorized embankment in Sodegaura City that collapsed during Typhoon 25 in September.
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Chiba Prefectural Police arrested three men on Oct. 7 on suspicion of violating the prefecture's residual soil ordinance by building an unauthorized embankment on private land in Ichihara City, Chiba Prefecture. The three are connected to the Ichihara City civil engineering company Sanwa Shokai, according to the reports. [ 1 , 2 , 5 , 6 , 7 ]
Nippon TV, Sankei Shimbun and Mainichi Shimbun identified one of those arrested as Nobuyuki Ozawa, 47, the company's representative director. Sankei named the other two as company employee Kazuya Takeda, 60, and construction worker Yoshiyuki Oshima, 59. Sankei and Mainichi reported that police believe Ozawa gave the instructions while the other two served as site manager and as the person who carried out the work. Mainichi said police did not disclose whether the three admitted or denied the allegations. [ 2 , 5 , 7 ]
According to the reports, the site in Ichihara's Nishikuniyoshi district covered about 10,000 square meters and the embankment stood up to about 15 meters high. Yomiuri Shimbun said the suspects are suspected of filling an area of more than 3,000 square meters without the governor's permission between April and November 2025, and that one of them brought in about 325 cubic meters of soil between September and October knowing it was unauthorized. Sankei and Mainichi said the prefecture ordered the full removal of the soil by February 2026 and that the order was not obeyed; Sankei said the prefecture filed a complaint with Ichihara police in March this year. [ 1 , 2 , 5 , 7 ]
The case is also tied to Typhoon 25 in September. Yomiuri reported that Sanwa Shokai had received administrative guidance from Sodegaura City over an embankment built without permission that collapsed in the typhoon. Nippon TV said the collapsed embankment was in Sodegaura's Otake district and that police are investigating whether the company was involved in other illegal embankments in the prefecture. [ 1 , 2 , 6 ]
Mainichi, citing the prefecture, said four embankment collapses were confirmed after the typhoon, in Sodegaura, Shisui and Ichihara, and that at Otake soil flowed into rice fields and roads; it said city and prefectural authorities repeatedly instructed a contractor to remove the soil between July 2025 and about July 2026 without success. Sankei said embankments built by the company and others elsewhere in the prefecture collapsed and soil flowed onto roads. [ 5 , 7 ]
Why it matters
The case links a local ordinance violation to a landslide site that damaged farmland and roads after Typhoon 25, putting attention on how removal orders and administrative guidance are enforced in Chiba Prefecture. Police say they are also looking into the company's involvement in other illegal embankments, suggesting the investigation may widen. The documents give no further indication of policy consequences.
Key facts
- Chiba prefectural police arrested three men on Oct. 7 on suspicion of violating the prefecture's residual soil ordinance over unauthorized embankment work in Ichihara City. [ 1 , 2 , 5 , 6 , 7 ]
- One of those arrested is Nobuyuki Ozawa, 47, representative director of the Ichihara City civil engineering company Sanwa Shokai. [ 2 , 5 , 7 ]
- The embankment in Ichihara's Nishikuniyoshi district covered about 10,000 square meters and stood up to about 15 meters high. [ 2 , 5 , 7 ]
- Sankei Shimbun and Mainichi Shimbun report that the prefecture ordered the soil removed and filed a complaint with police in March this year. [ 5 , 7 ]
- The company had received administrative guidance over an unauthorized embankment in Sodegaura City's Otake district that collapsed during Typhoon 25 in September. [ 1 , 2 , 6 , 7 ]
- Nippon TV and Mainichi report that four embankment collapses were confirmed in Chiba Prefecture after Typhoon 25. [ 2 , 7 ]
Confirmed by several sources
- Chiba prefectural police arrested three men on Oct. 7 on suspicion of violating the prefecture's residual soil ordinance over unauthorized embankment work in Ichihara City. [ 1 , 2 , 5 , 6 , 7 ]
- One of those arrested is Nobuyuki Ozawa, 47, representative director of the Ichihara City civil engineering company Sanwa Shokai. [ 2 , 5 , 7 ]
- The embankment in Ichihara's Nishikuniyoshi district covered about 10,000 square meters and was up to about 15 meters high. [ 2 , 5 , 7 ]
- The prefecture filed a complaint with police in March this year over the Ichihara embankment. [ 5 , 7 ]
- Sanwa Shokai received administrative guidance over an unauthorized embankment in Sodegaura City's Otake district that collapsed in Typhoon 25. [ 1 , 2 , 6 , 7 ]
- Four embankments in Chiba Prefecture collapsed due to Typhoon 25, with the Sodegaura Otake site among them and Sanwa Shokai subject to administrative guidance over that site. [ 2 , 7 ]
Still unclear
- Whether the three suspects admit or deny the allegations. Mainichi Shimbun says police did not disclose their responses, and no other document states a position.
- The exact timing of the prefecture's removal order. Yomiuri Shimbun says the representative director was ordered in November last year to remove all the soil, while Sankei Shimbun and Mainichi Shimbun say removal was ordered by February 2026.
- Whether Sanwa Shokai is involved in other illegal embankments in Chiba Prefecture. Nippon TV says police are investigating this; no other document confirms or elaborates.
- The amount of soil one suspect is alleged to have brought in. The figure of about 325 cubic meters is stated only by Yomiuri Shimbun.
What local media are saying
Timeline, local time
- Yomiuri Shimbun reports three arrests over unauthorized landfill in Ichihara and says the company had received administrative guidance over a Sodegaura embankment that collapsed in Typhoon 25. [ 1 ]
- Nippon TV reports the Ichihara site covered more than 10,000 square meters and was over 15 meters high, and names Ozawa. [ 2 ]
- Sankei Shimbun reports the names of the other two suspects and that the prefecture filed a complaint with police in March this year. [ 5 ]
- Mainichi Shimbun reports the prefecture counted four embankment collapses after Typhoon 25, including Sodegaura Otake, where soil flowed into rice fields and roads. [ 7 ]