At least four people have been killed and thousands of travellers stranded after record-breaking rainfall struck Chiba prefecture, a densely populated region immediately east of Tokyo, on Thursday night and into Friday. The Japan Meteorological Agency issued its highest level 5 warning for heavy rain and landslides across the prefecture — the first time such an alert has been declared there — as rainfall reached 115mm per hour in some areas, roughly equivalent to the entire month of August's average precipitation falling in a single hour. Over a 24-hour period, some parts of Chiba recorded more than 360mm of rain, the highest volume of precipitation ever recorded in the country.

Among the dead were a man believed to be in his 60s or 70s found floating on a flooded road in Ichikawa City, and a 66-year-old woman whose car became submerged in floodwaters in Sakura City. Two further individuals were found collapsed on streets and later died. A fifth person was feared dead and a sixth remained unaccounted for. Soldiers from Japan's Ground Self-Defence Force were dispatched to assist with rescue operations, evacuating around 4,000 people stranded for hours at Soga train station. Evacuation advisories were issued for more than 230,000 people, and at their peak, up to 45,000 households were left without power. Some 80 homes suffered direct flooding.

The disaster unfolded during Bon, one of Japan's most important Buddhist holiday weeks and among its busiest travel periods. Nearly 7,000 passengers spent the night at Narita, one of Tokyo's main international airports, after train services connecting the terminal to the wider region were suspended. Around 1,800 people sought shelter inside the Chiba prefectural government building. Rail services partially resumed Friday morning with significant delays, while flights at Narita were reported to be operating normally. Chiba Governor Toshihito Kumagai described the event as