The FX board's sharpest move today was the yen and won falling together. USD/JPY rose to 154.90 and USD/KRW to 1356.6, with two core Northeast Asian currencies under synchronized pressure. For Japanese and Korean refiners, crude is bought in dollars, so a weaker local currency immediately lifts feedstock cost.

The flip side is that their exported products are settled in foreign currency; a softer currency makes Japanese and Korean barrels cheaper in third-country markets and strengthens competitiveness. That creates a rebalance: domestic refining margin squeezed by feedstock cost, overseas sales margin supported by the exchange rate. Which side wins depends on each refiner's crack capability and export destination.

For the SNSUC re-export book this touches the landed-cost math on ESPO and other Northeast Asian deliveries directly. If Korean and Japanese refiners cut buying on cost pressure, Middle East-to-Northeast-Asia spot flows shift; if they instead push exports to grab market share, Asian distillate and gasoline supply grows. The two paths pull regional spreads in opposite directions and must be tracked separately.

The yuan tells a different story, with USD/CNY at 6.7124, essentially flat. That keeps CNY-denominated landed costs for Chinese buyers stable, making the yuan the anchor in the region. When running cross-region arbitrage, treat Japanese and Korean cost swings as the variable and China's stability as the baseline.