Yoshiko Kodama, 87, has kept her Nagano‑city sento alive for 138 years, but the surge in oil prices triggered by the Iran war threatens to shut it down. Her bathhouse burns roughly 2,000 liters of heavy oil each month, and the Japan National Sento Association reports operating costs have risen as much as 50% since the conflict began, and threatens a cultural legacy.

Sento have long served as low‑cost communal baths for Japan’s aging alone‑living population, with entry fees capped near 500 yen ($3). Declining patronage, a shortage of successors and competition from private home tubs already squeezed margins; now, higher fuel bills push many of the remaining 1,493 operators toward reduced hours or closure, according to industry surveys, especially in rural prefectures where alternatives are scarce.

Without emergency subsidies or permission to raise fees, owners like Kodama risk draining personal pensions to keep doors open. The association has petitioned Tokyo for oil grants and price‑cap flexibility, but officials argue that dwindling facilities may be beyond rescue. As the energy shock persists, Japan’s historic public‑bath culture faces an accelerated decline, for the social fabric of neighborhoods.