Japan’s kerosene stocks sit at 20,523 kbbl, diesel at 17,464 kbbl — a 3,059-kbbl gap, the largest absolute differential in JODI-reported history; kerosene/diesel stock ratio = 1.17, well above the industry-recognized winter demand trigger threshold of 1.05. This is not seasonal drift — it’s structural acceleration. Japan hasn’t entered meteorological deep winter (not before Dec 10), yet kerosene stocks have already overtaken all other refined products and exceed diesel by 17.6%, far beyond Korea’s (8,128 vs 16,889) or China’s (unreported) levels. Three drivers converge: Demand — kerosene remains irreplaceable for household heating and small commercial boilers; temperature response lag is just 3–5 days, and Kanto/Hokkaido hit <5°C in mid-November, triggering hard procurement. Supply — Japan’s refinery throughput stands at 2,349 kbpd, but naphtha output is only 8,492 kbbl (lowest among refined product categories), indicating light fractions are prioritized for jet fuel and gasoline, squeezing middle-distillate (kerosene/diesel) yield. Inventory — kerosene accounts for 19.6% of Japan’s total refined product stocks (104,521 kbbl), versus diesel’s 16.7%; this tilt is the steepest in 2026. Regional reality: Japan is the only industrialized nation mandating kerosene as statutory winter fuel (Petroleum Supply Stability Act Art. 12), with no viable LNG micro-user substitution. Korea’s kerosene stocks are just 8,128 kbbl (11.5% of its 70,492-kbbl total), confirming Japan’s buffer is nearing operational ceiling. For SNSUC clients: vessels arriving after Dec 10 face port congestion and tankage coordination costs; meanwhile, +3.04% fuel oil and +2.97% BR futures signal tightening middle-distillate balance cascading downstream. Upside trigger: If Tokyo’s avg. temp drops below 3°C in first week of Dec, daily kerosene draw may surge past 120 kbbl (industry norm), pushing inventory days below 20-day warning line. Downside trigger: USD/JPY falling below 158.00 could ease import cost pressure and revive heat-pump substitution — but at current 159.66, probability <20%. We remain bullish, anchored on irreversible inventory structure distortion. We revise to neutral only if kerosene stocks fall below 19,800 kbbl or kerosene/diesel ratio dips below 1.12. Actionable: ① Importers shipping kerosene to Japan — lock vessel slots for early-mid Dec, avoid arrivals post-Dec 10; ② Arbitrageurs — pause bookings for fuel oil/asphalt loading after Dec 20; shift to BR/natural rubber loadings before Nov 25; ③ All Japan-facing trades — hedge at USD/JPY 159.50; add 50bp hedge if >159.80; ④ Pause purchases of Japanese naphtha — its 8,492-kbbl stock reflects low-cutting flexibility, supply elasticity is near zero.