Almost 2 years ago, I wrote a research piece that, at that time, left many in utter disbelief: “A PEEK INTO THE FUTURE: USD/JPY ROAD TO 300.” In that piece, I calculated what should have been the JPY fair exchange rate against the USD at that time based on the following concepts:
- Japan’s debt would have continued to expand.
- BOJ hiking rates would have meant a bigger need for money printing, adding even more debt onto Japan’s debt pile, in order to allow Japan to keep servicing its public debt.
- Inflation in Japan would have pushed JGB yields up, requiring even more debt monetization efforts by the BOJ.
- Because of never-ending money printing, inflation would have been pushed even higher, creating a “doom-loop” Japan could not escape, and that I explained in great detail a long time ago in: “EXPLAINING AND SIMPLIFYING THE JPY (COUNTERINTUITIVE) DOOM LOOP.”
Fast forward 2 years, and not only has the situation not improved, but of course, worsened against all rosy government projections that are constantly so dead wrong. Now add the 2026 oil crisis into the equation.
First of all, why is Japan uniquely exposed to an oil shock? Japan is one of the most energy-import-dependent major economies. That matters because an oil shock is not just a price move; it is an external tax that Japan must pay in foreign currency.
- The current account channel flips fast: When crude and LNG prices rise, Japan’s import bill rises immediately, while export volumes do not automatically rise enough to offset it. The trade balance can swing from surplus to deficit quickly, pushing the overall current account down significantly. That reduces the steady “structural” flow of foreign currency into Japan, and forces Japanese corporates and utilities to buy more USD to pay for energy. More USD demand, less USD supply.
- Energy is a high pass-through input in Japan’s CPI: Japan imports the marginal barrel. Higher oil raises gasoline, electricity, and transport costs, and then this bleeds into food and manufactured goods through logistics and packaging costs right away. That will squeeze real wages and consumption.
- The policy reaction function is asymmetrical: If the BOJ is still constrained by public-debt dynamics, it cannot comfortably hike rates to defend the currency without raising the government’s interest burden and forcing fiscal or monetary offsets. So Japan can face inflation pressure from oil while still not being able to tighten meaningfully.
Secondly, why Japan’s SPR is not the macro buffer people think it is. Japan’s strategic petroleum reserve helps with physical supply continuity and short-term disruptions. It is not designed to, and cannot, neutralize a multi-quarter price shock.
- If oil is expensive globally for months, drawing SPR barrels does not make the marginal global barrel cheap. It can smooth delivery logistics and prevent panic, but it does not “reset” Japan’s import price.
- Even if the headline stock number looks large, the economy runs on flow, not stock. The maximum daily drawdown rate and distribution constraints mean an SPR can replace only a portion of normal consumption for a limited period. Currently, the maximum drawdown of Japan’s SPR is estimated to be 1.7 million barrels of oil per day, while Japan consumes 3 million barrels per day of oil. Using simple math, this means that, no matter what, Japan will be facing a 1.3 million barrels per day oil supply shortage. Furthermore, let’s never forget that Japan imports virtually 100% of all the oil it consumes.
- Japan imports not just crude but also relies on global pricing for refined products, LNG-linked pricing structures, shipping insurance, and freight. Those prices move with the global marginal barrel, not with the existence of reserves in storage.
Lastly, here is how higher oil prices mechanically feed the JPY depreciation because it tends to weaken the JPY through three reinforcing loops:
- Terms-of-trade deterioration, weaker trade balance, more USD buying: Utilities, refiners, and large importers must buy more USD (and other currencies) to pay for energy. This is a direct FX flow.
- “Imported inflation” without the rate support: In many countries, higher oil prices lead to higher policy rates, supporting the currency. If Japan cannot raise rates enough, the real rate differential can widen against Japan, encouraging capital outflows and carry trades funded in JPY. However, since we know Japan is stuck in a “monetary doom loop”, in its specific case, higher interest rates will mean even higher devaluation pressures on its currency.
- Risk sentiment plus JPY carry trade dynamics: When oil spikes because of geopolitics or supply disruption, global risk premia rise. If Japan is simultaneously running a larger energy-import deficit, JPY can lose its perceived safe-haven bid. Meanwhile, if Japan’s yield curve remains suppressed, shorting JPY to buy higher-yielding assets remains attractive. This is the reason why Japan continues threatening traders with direct currency interventions (”USD/JPY pulls back from red line as Japan threatens intervention”). However, as we know, these interventions are very dangerous for the market’s stability since they can spark significant volatility across asset classes with domino effects all around the globe, as it happened all the previous times Japan pulled the trigger. Furthermore, by selling its monetary reserves to briefly strengthen the currency, Japan is de facto weakening its currency in the long term since there will be less foreign currency reserves against the ever-growing supply of JPY in the market. Just simple algebra here.
The US Treasury is not blind to what’s happening in Japan. It cannot be. When the world’s biggest creditor nation to the US is trapped between an oil shock and an un-defendable currency, the consequences land directly on America’s bond market. That is why the “cap” matters. Keeping WTI near 100$ and Brent near 110$ is not some abstract inflation fight. It is a pressure valve on Japan’s external accounts. Above those levels, Japan’s energy import bill turns into a relentless USD vacuum, the JPY weakens faster, and Tokyo is forced closer to the one lever it still has: selling reserves.
But reserve selling is not free. When Japan defends the JPY by dumping U.S. Treasuries and dollar assets, it adds supply to the market right when the U.S. is already funding massive deficits. That pushes Treasury yields up mechanically, tightening financial conditions at the worst moment. And here is the real nightmare for Washington: FX intervention is a volatility grenade. A sudden, forceful JPY spike can rip through carry trades, blow up crowded positions, and trigger cross-asset deleveraging. In a fragile tape, that chain reaction does not stop at FX. It hits credit, it hits liquidity, and it can end where cascades end: a disorderly stock market drawdown that turns into a crash similar to what happened in 2024 and was nearly avoided at the last minute.
Oil is the fuse, the yen is the accelerant, and the Treasury market is the transmission line. The US Treasury knows the math. The market will be forced to price it anyway, but in the meantime, it is of paramount importance to try to save private Takaichi.