# 2026年9月25日（金）コメンテーター：小泉悠

- Show: 飯田浩司のOK! Cozy up！ Podcast【最新回のみ】
- Published: 2026-09-25
- Canonical: https://podc.club/en/episode/1366187377_cf7c9687abd6.html
- Audio: https://traffic.omny.fm/d/clips/67122501-9b17-4d77-84bd-a93d00dc791e/3c31cad9-230a-4a5f-b487-a9de001adcdd/16b70ece-0c65-4206-83bf-b4cf017a75fb/audio.mp3?utm_source=Podcast&in_playlist=47a5ec59-4c22-496d-b71d-b2a4001ebd5d
- Source: Edited from a machine transcript of the first 30 minutes of the episode. Not an official summary.

Typhoon No. 25 caused widespread flooding around Inba Lake in Chiba Prefecture, triggering repeated explosions and fires at a solar power facility in Narita City. Military analyst Yu Koizumi (小泉悠) joined the program to discuss those disasters alongside the near-simultaneous U.S.-China summit on AI supremacy and Taiwan, Prime Minister Takaichi's (高市) 30-hour Washington visit, and an AI-assisted hacking incident targeting Australian government agencies.

## What this episode answers

### Why did Typhoon No. 25 flood such a vast area around Inba Lake in Chiba, and what impact has it had on the region?

Typhoon No. 25's heavy rains inundated a wide area around Inba Lake because Chiba's aging infrastructure and narrow key roads with few detour routes could not handle the volume, submerging roads like Routes 464 and 465; the flooding has disrupted daily life with commutes stretching to two and a half hours and buses too full to reach Tokyo, and it has exposed risks for the dense cluster of data centers in Chiba New Town where power demand is surging.

### Is the U.S.-China relationship shifting from confrontation toward coexistence, and where does the line on Taiwan actually stand?

There is a peaceful-coexistence mood similar to the 1960s U.S.-Soviet relationship, with both sides avoiding outright rupture, as symbolized by the leaders' understated clothing signaling coexistence over confrontation; however, Taiwan remains the unresolved core issue with no clear demarcation line, since China claims Taiwan as its own while the U.S. and neighboring countries stop well short of accepting that claim, leaving the fundamental problem simply deferred.

### What was the strategic logic behind Prime Minister Takaichi's 30-hour sprint to meet Trump, and why does Japan's handling of the ICC matter so much?

Takaichi's rapid 30-hour Washington trip let Japan deliver its inputs to Trump before any U.S.-China deal could be struck at the summit, a rational and strategic use of timing; her raising the ICC despite Trump's strong opposition matters because showing the spine to speak up to an ally on an uncomfortable topic is being watched by both Russia and China as an indicator of how much weight Japan carries as an actor.

### What structural reason prevented firefighters from extinguishing the flooded solar facility in Narita as it kept exploding?

Firefighters could not extinguish the fire because water seeping into the high-voltage panels caused short circuits, and as long as sunlight kept reaching the panels they continued generating power and could not simply be switched off, so the fire only burned out naturally after about two and a half hours.

### How can humans respond to a form of cyberwarfare in which AI generates malware and patches in real time, with no room for human intervention?

The article does not describe how humans can respond to this AI-driven, human-intervention-free cyberwarfare beyond noting that such attacks (as exercised in U.S. military drills) occur too fast for human involvement and that many intrusions likely go undetected.

## Article

## Typhoon No. 25 and Flooding Around Inba Lake — A Local's Perspective

Heavy rains from Typhoon No. 25 inundated a wide swath of Chiba Prefecture around Inba Lake. Commentator Yu Koizumi, who grew up on the eastern edge of Matsudo City, said he was struck by footage circulating on social media: National Routes 464 and 465 — roads he used every day — were underwater. Chiba has long seen itself as a mild, agriculturally prosperous prefecture with few disasters, yet flooding has struck repeatedly this year. Landslides also hit the Miura Peninsula in Kanagawa, prompting Koizumi to draw on a personal observation: having visited Bucha in Ukraine in April, he noted that news of damage to places you have actually been hits the brain in a completely different way. He added that he makes a point of going anywhere he can, precisely so that unfamiliar place names do not remain abstract.

The flooding also exposed risks for the dense cluster of data centers in Chiba New Town, a zone where electricity demand has been surging. Listeners wrote in to report commutes stretching from the usual 30 minutes to two and a half hours, and buses from the Sodegaura area too full to reach central Tokyo. Koizumi argued that as infrastructure built during Japan's high-growth era reaches the end of its design life, the country needs to rethink resilience — including the narrowness of key roads and the scarcity of detour routes.

## The U.S.-China Summit — A "Peaceful Coexistence" Mood, but Taiwan's Red Line Undrawn

The U.S.-China summit, which dominated front pages, produced a two-month extension of the trade truce. Koizumi drew a parallel with the U.S.-Soviet peaceful coexistence posture of the 1960s, saying there is now a similar sense between Washington and Beijing that outright rupture must be avoided. He even noted that the two leaders' understated, unshowy clothing in official photographs conveyed a deliberate message of coexistence over confrontation. The core unresolved issue, however, remains Taiwan. Unlike the Cold War's Iron Curtain, there is still no clear demarcation line: China insists Taiwan is part of China, while the United States and neighboring countries stop well short of accepting that claim. The fundamental problem has simply been deferred again.

Koizumi had attended the Baltic Defence Annual Conference in Estonia until the day before the summit — a 20-year-old forum at which a Japan panel appeared for the first time this year. He reported that the central question there was exactly how far Europe can rely on U.S. engagement, and concluded: "The problems Europe faces and the problems Japan faces on the Asia front are more similar than I had expected."

## Prime Minister Takaichi's Washington Visit and Japan's Stance on the ICC

Prime Minister Takaichi returned home after addressing the UN General Assembly and holding a bilateral meeting with President Trump — a Washington stay of roughly 30 hours. Koizumi called the timing rational: by meeting Trump right before the U.S.-China summit, Japan was able to deliver its inputs before any U.S.-China deal could be struck. He warned that the real test is whether Washington perceives Japan as a serious partner rather than a compliant appendage — pointing out that Putin has long treated Japan in the latter fashion, and that this must not be allowed to continue.

On Takaichi raising the ICC in her talks with Trump — a topic the president strongly opposes — Koizumi said the ability to speak up to an ally on an uncomfortable subject matters enormously. "Both Russia and China are watching to see how far Japan will push on the ICC question. How much spine Japan shows there is a significant indicator of its weight as an actor."

## Explosions at Narita's Flooded Solar Facility — The Compound Risk of Water and High Voltage

A solar power installation in Narita City that had been inundated by the typhoon caught fire repeatedly and produced multiple explosion sounds. Firefighters could not approach, and the blaze extinguished itself naturally about two and a half hours after the first emergency call. Koizumi explained the structural reason: water seeping into panels carrying high-voltage current causes short circuits, and as long as sunlight reaches the panels they continue generating power and cannot simply be switched off. From a security standpoint he acknowledged that distributed renewable energy improves resilience in principle, but argued that in flood-prone Japan the siting risks of solar installations must be rigorously assessed at the building-permit stage. He closed with a broader warning: "A major typhoon and a military crisis could easily occur simultaneously. Infrastructure cannot be engineered to the absolute minimum — it needs slack built in, or there will be nothing left to draw on when it matters."

## AI and Cybersecurity — War at a Speed That Excludes Human Judgment

Multiple outlets reported that an OpenAI AI system had been used to hack Australian government agencies. Koizumi noted that AI has no ethical sense, making it acutely dangerous as a hacking tool. Drawing on a discussion with students at the University of Tokyo's Research Center for Advanced Science and Technology, he described a scenario already exercised in U.S. military drills: an AI probes a system for vulnerabilities, generates tailored malware on the spot in real time, and penetrates the target — while the defending side's AI instantly writes a patch. The entire exchange occurs at a speed that leaves no room for human intervention. The Australian case was one that was detected; Koizumi suggested that far more intrusions are happening without ever being caught.

## Takeaways

- Typhoon No. 25's widespread flooding around Inba Lake triggered explosive fires at a Narita solar facility and raised blackout risks for Chiba New Town's data centers, exposing fundamental gaps in Japan's infrastructure resilience design.
- The U.S.-China summit landed on a note of coexistence with a two-month trade-truce extension, but the Taiwan question remains unresolved, and Prime Minister Takaichi's compressed Washington visit — timed just before the summit — tested whether Japan can assert itself as a partner rather than a subordinate.
- Cyberwarfare in which AI generates malware and defensive patches in real time, with no space for human judgment, has already become a reality, and the use of ethically unconstrained AI as a hacking instrument poses a deeply serious threat.