US-Iran Conflict Threatens Japan's Economy, Shakes BOJ Rate Plans
The US-Iran military conflict following the assassination of Supreme Leader Khamenei is imposing a double burden of "economic cooling × price increases" on the Japanese economy, which relies 90% on Middle Eastern oil. The Bank of Japan's carefully advanced interest rate normalization scenario is being fundamentally shaken by this geopolitical shock.
── Understand in 3 points ─────────
- • Bank of Japan Governor Kazuo Ueda stated at the House of Representatives Financial Affairs Committee on March 4, 2026, regarding the impact of the Iran situation on the Japanese economy, that "while there is concern that rising crude oil prices could cool the economy, there is also a possibility that they could push up prices," indicating his intention to closely monitor future developments.
- • On February 28, 2026, the United States and Israel launched military operations against Iran. Explosions were confirmed in multiple cities, including Tehran, and President Trump announced that Supreme Leader Khamenei had been killed. Iranian casualties exceeded 200.
- • The Islamic Revolutionary Guard Corps (IRGC) retaliated with missile and drone attacks on US military bases in Bahrain (US Fifth Fleet headquarters), Qatar, and the UAE. All US military bases and Israeli military facilities across the Middle East were declared targets.
── NOW PATTERN ─────────
The escalation spiral of the US-Iran military conflict is directly hitting Japan's path dependency on Middle Eastern oil (90% reliance), creating a crack in the alliance between the Japan-US alliance and Middle Eastern energy security.
── Probability and Response ──────
🟡 Base 50% — Crude oil prices do not exceed $100 per barrel, IRGC retaliatory attacks remain sporadic, US military targets do not expand, international mediation efforts (Oman, China) become active, the BOJ states it will "assess the situation" at its next meeting.
🟢 Optimistic 20% — Direct negotiation channels open between the US and Iran, IRGC retaliatory actions cease, crude oil prices fall below $90 per barrel, China exerts influence over Iran, a war powers resolution is passed in the US, limiting military action.
🔴 Pessimistic 30% — Iran lays mines or conducts anti-ship attacks in the Strait of Hormuz, crude oil prices break $120 per barrel, tanker insurance premiums surge leading to halted navigation, the US mentions large-scale ground operations, signs of regime collapse emerge in Iran, escalating retaliatory actions.
📡 The Signal — What Happened
Why it matters: The US-Iran military conflict following the assassination of Supreme Leader Khamenei is imposing a double burden of "economic cooling × price increases" on the Japanese economy, which relies 90% on Middle Eastern oil. The Bank of Japan's carefully advanced interest rate normalization scenario is being fundamentally shaken by this geopolitical shock.
- Statement — Bank of Japan Governor Kazuo Ueda stated at the House of Representatives Financial Affairs Committee on March 4, 2026, regarding the impact of the Iran situation on the Japanese economy, that "while there is concern that rising crude oil prices could cool the economy, there is also a possibility that they could push up prices," indicating his intention to closely monitor future developments.
- Military Situation — On February 28, 2026, the United States and Israel launched military operations against Iran. Explosions were confirmed in multiple cities, including Tehran, and President Trump announced that Supreme Leader Khamenei had been killed. Iranian casualties exceeded 200.
- Retaliatory Attacks — The Islamic Revolutionary Guard Corps (IRGC) retaliated with missile and drone attacks on US military bases in Bahrain (US Fifth Fleet headquarters), Qatar, and the UAE. All US military bases and Israeli military facilities across the Middle East were declared targets.
- Naval Combat — On March 4, 2026, a US submarine sank an Iranian warship (over 80 of 180 crew members died, 32 rescued). Secretary of Defense Hegseth announced.
- Energy Dependence — Approximately 90% of Japan's crude oil imports come from the Middle East, with Saudi Arabia (approx. 40%), UAE (approx. 25%), Qatar (approx. 10%), and Kuwait (approx. 8%) being the main suppliers. The Strait of Hormuz is a transit point for 20% of the world's oil and 30% of its LNG.
- Strategic Reserves — Japan holds strategic oil reserves for approximately 160 days, but severe impacts are unavoidable if a long-term supply disruption occurs.
- Monetary Policy — The BOJ lifted negative interest rates in 2024, raising the policy rate to 0.25%, and had hinted at gradual rate hikes to 1-1.5% by 2026. However, the Iran situation is casting uncertainty over this normalization path.
- International Reaction — Spanish Prime Minister Sánchez declared "no" to US military action. In the UK, mortgage rates are rising, and household energy costs are expected to increase by £160 annually.
- Market Impact — Bitcoin plunged below $67,000 before rebounding to over $74,000. The Japanese stock market is under pressure from rising energy costs.
- Political Reaction — On March 2, 2026, LDP Policy Research Council Chairman Kobayashi stated at a joint LDP meeting that "stability in the Middle East is directly linked to Japan's security and the lives of its citizens," urging the government to make diplomatic efforts to de-escalate the situation.
- US Domestic Politics — The US House of Representatives is scheduled to vote on an Iran War Powers Resolution. Representative Warren Davidson (R) criticized the Trump administration for not effectively explaining its military objectives.
- Succession Issue — Following the assassination of Supreme Leader Khamenei (February 28), the selection of a successor by Iran's Assembly of Experts is a key focus. When Ayatollah Khomeini died in 1989, a successor (Khamenei) was decided in three days, but this time, due to the sudden nature of the assassination, there is no letter of designation, posing a risk of prolongation.
Behind BOJ Governor Ueda's seemingly modest remark of "closely watching developments" lies a structural vulnerability of the Japanese economy and a pattern of oil shocks that has recurred for half a century.
The history of Japan and energy crises dates back to the First Oil Crisis in 1973. When crude oil prices quadrupled due to the oil embargo by Arab nations, Japan was hit by severe "runaway inflation." At the time, Japan relied on imports for over 99% of its oil, and consumer prices rose 23% year-on-year. A panic buying spree for toilet paper occurred, and the Kakuei Tanaka administration enacted "emergency oil measures." This experience became the origin of Japan's energy security policy.
During the Second Oil Crisis, triggered by the Iranian Revolution in 1979, Japan was able to respond relatively early by leveraging lessons from the first crisis, but still experienced "stagflation" with rising prices and economic recession. Through these two crises, Japan advanced measures in three directions: establishing an oil stockpiling system, developing energy-saving technologies, and shifting towards nuclear power generation. However, the fundamental problem—overwhelming reliance on Middle Eastern oil—has not been resolved even after half a century.
The Fukushima Daiichi Nuclear Power Plant accident in 2011 directly hit nuclear power, another pillar of Japan's energy security. After the accident, almost all nuclear power plants were shut down, and Japan's energy import dependency rose to approximately 90%. Imports of LNG (liquefied natural gas) surged, making Japan the world's largest LNG importer. 30% of the world's LNG passing through the Strait of Hormuz is directly linked to Japan's electricity supply.
Russia's invasion of Ukraine in 2022 once again highlighted the vulnerability of energy security. As Europe struggled to break away from Russian gas, Japan also faced a surge in LNG prices. Electricity bills rose by 40%, pressuring both households and businesses.
And now, the US-Iran military conflict since late February 2026 is realizing the most dangerous scenario within this historical context. The unprecedented assassination of Supreme Leader Khamenei signifies not merely a fluctuation in crude oil prices, but the destabilization of the Middle East's political structure itself. If Iran retaliates by obstructing passage through the Strait of Hormuz, Japan's oil and LNG supply will immediately fall into crisis.
For the BOJ, this situation has arrived at the worst possible time. Governor Ueda lifted negative interest rates in 2024 and has been cautiously and gradually advancing interest rate normalization. He had indicated a policy of raising the policy rate to 1-1.5% by 2026, and the Japanese economy was finally seeing a path out of deflation. However, the surge in crude oil prices presents the BOJ with a cruel dilemma.
Price increases due to high crude oil prices (cost-push inflation) are fundamentally different from the "virtuous cycle inflation accompanied by wage increases" that the BOJ targets. Rather, they pressure corporate profits, erode consumers' real purchasing power, and act to cool the economy. Nevertheless, because price indicators are rising, pressure to "raise interest rates to combat inflation" and pressure to "lower interest rates to prevent economic deterioration" arise simultaneously. This is what Governor Ueda means by "while there is concern that rising crude oil prices could cool the economy, there is also a possibility that they could push up prices."
It is still fresh in memory that former Prime Minister Shinzo Abe visited Iran in 2019 and attempted to mediate between the US and Iran. Japan has traditionally maintained its own diplomatic channels with the Middle East, but there are structural limits to how much of an independent stance it can take within the framework of the Japan-US security alliance. Policy Research Council Chairman Kobayashi's reference to "diplomatic efforts" reaffirmed Japan's traditional stance of balanced diplomacy, seeking a diplomatic solution rather than military support for the US.
The delta: Governor Ueda's "closely watching developments" remark indicates the reality that the BOJ's carefully designed interest rate normalization path is being fundamentally shaken by an external shock originating from the Middle East. The mention of "risks of both economic cooling and price increases" signifies vigilance against the worst-case scenario for a central bank—cost-push stagflation. This is not merely "watching," but likely suggests a slowdown or freeze in the pace of rate hikes.
🔍 Between the Lines — What the News Isn't Saying
Behind Governor Ueda's statement of "closely watching developments" are three unspoken realities. First, the inconvenient truth that military actions by its ally, the United States, are directly threatening the Japanese economy. Second, the BOJ's desire to avoid the market perceiving a "abandonment of the normalization path," even though its planned rate hike trajectory is already effectively heading towards a freeze. Third, the fundamental uncertainty for a central banker: the lack of current information to determine whether this crude oil price surge is "temporary" or "structural." "Closely watching" is a phrase used when there is nothing one can do.
NOW PATTERN
Escalation Spiral × Path Dependency × Alliance Strain
The escalation spiral of the US-Iran military conflict is directly hitting Japan's path dependency on Middle Eastern oil (90% reliance), creating a crack in the alliance between the Japan-US alliance and Middle Eastern energy security.
Intersection of Dynamics
The three dynamics—escalation spiral, path dependency, and alliance strain—are acting as a self-reinforcing trap for Japanese policymakers.
The escalation spiral between the US and Iran directly hits Japan's Middle East-dependent energy structure (path dependency), which Japan has built over half a century. Furthermore, Japan's ability to respond to this direct hit is structurally constrained by the framework of the Japan-US alliance (alliance strain). Japan cannot oppose US military action, yet it finds itself in the contradictory position where that military action threatens its own energy supply.
At the intersection of these three dynamics stands the Bank of Japan. The BOJ possesses only technical tools in the form of monetary policy, but the problems it faces are military, diplomatic, and structural. If it responds to inflation caused by high crude oil prices with interest rate hikes, it will cool the economy; if it refrains from raising rates, it will allow prices to rise. This is a "policy trilemma" where either choice will negatively impact the economy.
Historically, the phase where these three dynamics acted simultaneously—that is, Middle East military conflict (spiral) × energy dependence (path dependency) × alliance management (strain)—is strikingly similar to the structure of the First Oil Crisis in 1973. At that time, Japan was also caught between Arab nations and the United States, and ultimately secured oil supplies by adopting a pro-Arab stance under the name of "resource diplomacy." However, this time, the security ties with the United States are far deeper, making the same choice not easy.
The most dangerous scenario is if the escalation spiral leads to a blockade of the Strait of Hormuz. Japan's 160 days of oil reserves may seem sufficient at first glance, but if the global energy market falls into panic, soaring prices will hit the economy directly even before reserves are drawn down. The BOJ can only say it is "closely watching developments," but in reality, the preconditions for policy decisions are already beginning to crumble.
📚 History of Patterns
1973: First Oil Crisis — Arab Oil Embargo
Middle East military conflict → Oil supply disruption → Japan's consumer prices rise 23% → BOJ policy response difficult
Structural similarities with the present: Japan's structural energy vulnerability has not been resolved for 50 years, and the pattern of Middle East developments directly constraining Japan's monetary policy is recurring.
1979: Second Oil Crisis — Iranian Revolution
Iran's political regime change → Oil supply anxiety → Crude oil prices triple → Japan's stagflation
Structural similarities with the present: The mechanism by which Iran's regime change impacts the global energy market has not structurally changed. The current power vacuum after Khamenei's assassination follows a similar pattern.
2019: Strait of Hormuz Tanker Attacks — During PM Abe's Visit to Iran
US-Iran tensions → Tanker attacks in the Strait of Hormuz → Japan attempts mediation but fails → Oil prices rise
Structural similarities with the present: Japan's Middle East diplomacy is constrained by the US military posture, and its independent mediation efforts have limited effect. However, maintaining diplomatic channels itself has value.
2022: Russia's Invasion of Ukraine — Energy Crisis
Major power military action → Energy supply disruption → Price surge → Japan's electricity bills rise 40% → BOJ policy dilemma
Structural similarities with the present: Energy price increases due to geopolitical shocks are the most difficult external variable for central banks to address. Cost-push inflation cannot be resolved by monetary policy.
1990: Gulf Crisis — Iraq's Invasion of Kuwait
Middle East military conflict → Crude oil prices double → Acceleration of Japan's bubble economy collapse → Monetary policy shift
Structural similarities with the present: Middle East military crises have the power to accelerate turning points in Japan's economic cycle. This time, too, there is a possibility it will be a turning point for the BOJ's normalization cycle.
Patterns Revealed by History
The 50-year historical pattern reveals a strikingly consistent mechanism. The causal chain of military conflicts or political regime changes in the Middle East → surge in crude oil prices → impact on the Japanese economy → BOJ policy dilemma has been repeated.
Particularly noteworthy is the "limit of learning" in Japan's energy security. Since the First Oil Crisis in 1973, Japan has invested heavily in energy-saving technologies, oil stockpiling, and diversification of energy sources. However, the fact that Japan still relies 90% on Middle Eastern oil in 2026 means that this structural vulnerability is too deep to be overcome by policy efforts alone. The retreat of nuclear power due to the Fukushima nuclear accident further exacerbated this dependence.
History also shows that Middle East crises force the BOJ into "impossible choices." Raising interest rates in response to cost-push inflation cools the economy, while holding them steady fuels inflation. In both 1973 and 2022, the BOJ ultimately had no choice but to "wait." Governor Ueda's "closely watching developments" is merely the latest iteration of this historical pattern. However, this time, there is a qualitatively different danger compared to past cases, as the BOJ is precisely in the midst of a delicate policy shift towards interest rate normalization.
🔮 Next Scenarios
The US-Iran military conflict gradually de-escalates after several weeks to 1-2 months of limited engagement, due to international mediation efforts and military attrition on both sides. Passage through the Strait of Hormuz experiences sporadic disruptions but does not lead to a complete blockade. Crude oil prices remain elevated in the $90-100 per barrel range but do not significantly exceed $100.
The BOJ slows its pace of rate hikes, postponing the next hike by at least 3-6 months. Governor Ueda justifies a de facto rate freeze by stating he will "assess economic conditions." Core CPI temporarily rises to the 3% range due to high crude oil prices, but underlying inflation excluding energy stabilizes around 2%. The yen weakens slightly against the dollar, trading in the 145-155 yen range.
The Japanese government extends gasoline subsidies and implements measures to mitigate drastic changes in electricity and gas prices, easing the impact on households. The impact on GDP remains limited to an annual downside of approximately 0.3-0.5%. The LDP promotes de-escalation efforts through diplomatic channels, but visible results are limited.
Implications for Investment/Action: Crude oil prices do not exceed $100 per barrel, IRGC retaliatory attacks remain sporadic, US military targets do not expand, international mediation efforts (Oman, China) become active, the BOJ states it will "assess the situation" at its next meeting.
Strong international pressure and mediation by China and Oman lead to an early ceasefire agreement between the US and Iran. Iran's IRGC maintains its "avenging the Supreme Leader" rhetoric while suppressing substantial military escalation. The new leadership selection process focuses on internal power struggles, reducing incentives for external military action.
In this scenario, crude oil prices temporarily rise to the $85-90 per barrel range before returning relatively quickly to the low $80s. Passage through the Strait of Hormuz remains normal, and no energy supply disruptions occur.
For the BOJ, this is an "unexpected development," allowing it to continue its interest rate normalization path as planned. Governor Ueda implements rate hikes in the latter half of 2026, and the policy rate could reach 0.5-0.75% within the year. The yen stabilizes, and Japanese stocks perform robustly, particularly in the financial sector. Concerns about cost-push inflation recede, and the path to "virtuous cycle inflation" accompanied by wage increases is maintained.
Japan's diplomatic mediation efforts may also be recognized, enhancing its international presence. While direct diplomatic success like Prime Minister Abe's visit to Iran (2019) is unlikely, a scenario where Japan functions as a coordinator within the G7 framework is possible.
Implications for Investment/Action: Direct negotiation channels open between the US and Iran, IRGC retaliatory actions cease, crude oil prices fall below $90 per barrel, China exerts influence over Iran, a war powers resolution is passed in the US, limiting military action.
The US-Iran conflict escalates into a full-scale, long-term war, and Iran obstructs passage through the Strait of Hormuz. Multiple tankers are damaged by IRGC anti-ship missile and mine attacks, leading to a near-halt in navigation due to surging insurance premiums. Crude oil prices surge to $120-150 per barrel, marking a recurrence of the 1973-style oil shock.
In this scenario, the Japanese economy suffers a severe blow. Surging energy import costs expand the trade deficit, and the yen rapidly depreciates, breaking into the 160-170 yen range. Consumer prices reach an inflation rate of over 5%, and real wages turn significantly negative. The BOJ falls into a policy cul-de-sac, unable to "raise or lower interest rates."
The impact on corporate activities is immense, with supply chains disrupted, especially in manufacturing. Soaring electricity prices (potentially exceeding the +40% seen in 2022) directly hit households and small and medium-sized enterprises. Oil reserves begin to be drawn down, but releasing reserves amidst a global supply shortage has limited price stabilization effects.
In the worst-case scenario, the Japanese economy falls into stagflation (price increases under economic recession), and the fruits of the BOJ's 30-year battle against deflation—the carefully advanced interest rate normalization—could be nullified. The Takaichi administration faces declining approval ratings and is forced to expand energy subsidies through supplementary budgets, but fiscal capacity is limited.
Implications for Investment/Action: Iran lays mines or conducts anti-ship attacks in the Strait of Hormuz, crude oil prices break $120 per barrel, tanker insurance premiums surge leading to halted navigation, the US mentions large-scale ground operations, signs of regime collapse emerge in Iran, escalating retaliatory actions.
Key Triggers to Watch
- BOJ Monetary Policy Meeting — Whether Governor Ueda revises the rate hike outlook at his press conference: March 13-14, 2026
- US FOMC (Federal Open Market Committee) — Rate cut decision and remarks on the Iran situation: March 18-19, 2026
- Holding of the Assembly of Experts' session for successor selection in Iran: By May 28, 2026 (within 90 days of assassination)
- US House of Representatives vote on War Powers Resolution — Whether to limit the Trump administration's military actions in Iran: March-April 2026
- Occurrence of tanker damage or navigation obstruction in the Strait of Hormuz: March-June 2026 (constant monitoring during ongoing conflict)
🔄 Tracking Loop
Next Trigger: BOJ Monetary Policy Meeting March 13-14, 2026 — Whether Governor Ueda revises the rate hike outlook or strengthens references to "uncertainty" at his press conference will be a watershed moment. The official view on the Iran situation and crude oil prices will determine the future direction of monetary policy.
Continuation of this pattern: Tracking Theme: Geopolitical Shock and BOJ Interest Rate Normalization — The next milestones are the BOJ meeting on March 14, followed by the deadline for Iran's succession issue at the end of May, and then the presence or absence of policy coordination with the FOMC in June.
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