Japan's Central Bank Faces an Unwinnable Battle Amid Persistent Yen Weakness

Source: Wall Street Journal

From April 28 to May 27, Japan's Ministry of Finance spent 11.7 trillion yen to buy yen, the largest single-month foreign exchange intervention in Japanese history.

On June 30, the Japanese yen fell to 162.62 against the U.S. dollar—the lowest level since December 1986. On July 8, it touched this level again during intraday trading. Today, it continues to trade above 162.

$1.17 trillion, lasted less than six weeks.

It’s not that the Bank of Japan hasn’t tried. In June, the policy rate was raised to 1%, the highest in 31 years. Since ending negative interest rates in March 2024, cumulative rate hikes have exceeded 100 basis points. Combined with the ¥9.8 trillion intervention in 2024, the Ministry of Finance has spent over ¥21 trillion in dollar reserves over the past two years.

Goldman Sachs isn’t buying it. On July 6, strategist Karen Reichgott Fishman raised the one-year target for USD/JPY from 155 directly to 165—one of the most bearish forecasts on Wall Street. Market pricing suggests traders assign a 72% probability to reaching 165 before June 2027.

This is not a matter of "adding another 25 basis points." The Bank of Japan is facing a battle it was destined to lose from the start.

The foreign exchange market does not trade absolute values; it trades differences.

The Federal Reserve's benchmark rate is 3.50-3.75%, while the Bank of Japan's is 1%, a difference of 275 basis points. Latest CFTC data shows that hedge funds' net short positions in the yen are at their most extreme level in recent years.

275 basis points represent a trade repeated countless times daily: borrow yen—with inflation exceeding 3% and an interest rate of 1%, resulting in a real negative rate—convert to USD, and buy U.S. Treasuries yielding over 4.5%. Excluding exchange rate fluctuations, the annualized carry return exceeds 3%. Each additional depreciation of the yen adds further return.

This is not some kind of "market sentiment." This is a mechanism. Carry trades do not care whether the Bank of Japan raised rates by 25 or 50 basis points—they only care about the spread between the U.S. and Japan. As long as the Fed does not cut rates—while oil prices are surging, tensions in Iran are escalating, and the shadow of U.S. inflation has not dissipated—yen faces not just the Bank of Japan, but the entire gravitational field of the dollar system.

The 1.17 trillion yen intervention was absorbed by the market in less than six weeks not because the amount was insufficient, but because the direction was wrong.

More deadly than the U.S.-Japan interest rate differential is Japan’s fiscal policy—a chain tied around the Bank of Japan’s feet, tightening with every struggle.

The total budget for fiscal year 2026 is 122.3 trillion yen, a historical record. Of this, "debt service" — expenditures used to repay principal and interest on government bonds — amounts to 31.3 trillion yen, an increase of a full 3 trillion yen from last year’s 28.2 trillion yen, consuming one-quarter of the budget.

For every 4 yen the Japanese government collects in taxes, 1 yen goes to creditors.

Worse still, this number is accelerating.

The 10-year Japanese government bond yield has risen from 0.25% in 2022 to 2.88% today. The Japanese government isn’t repaying old debt—it’s issuing new debt to pay off old debt—government debt exceeds 250% of GDP, and annual maturing obligations are refinanced through new bond issuances, with new debt rates many times higher than those of the old debt. Of the ¥31.3 trillion in debt service costs, interest payments are growing far faster than principal repayments. Interest compounds on interest, and the snowball grows on its own.

If the 10-year Japanese government bond yield rises another 100 basis points—without needing to be overly aggressive, simply due to the Bank of Japan continuing to raise rates or even just tapering bond purchases—debt service costs would easily surpass 35 trillion yen, heading toward 40 trillion. At that point, for every 3 yen collected in taxes, 1 yen would go toward interest payments.

This is Japan’s central bank interest rate ceiling. It’s not inflation holding them back, nor politics—it’s the Ministry of Finance that did the math: if you raise rates by another 50 basis points, the yen might not appreciate by 100 points, but my interest bill will jump by trillions. The market understands this calculation too—so rate hikes don’t strengthen the yen; instead, they reinforce the market’s conviction that the Bank of Japan will ultimately be restrained by the Ministry of Finance.

Kamikawa Saeko's government has a fiscal stance that is the opposite of the Bank of Japan's.

In the 2026 fiscal year, defense spending exceeded 9 trillion yen, marking its 14th consecutive year of growth, with its share of GDP reaching 2% in fiscal year 2025. If the proposed suspension of the food consumption tax, currently under discussion by the ruling coalition, is implemented, it would result in annual revenue losses of 4 to 5 trillion yen. Various economic stimulus measures and household subsidies continue to be intensified. Nomura Securities warned at the beginning of the year that this "high-spending trade" model—where Japanese stocks rise, the yen weakens, and long-dated Japanese bonds come under pressure—mirrors the market pricing logic of former UK Prime Minister Liz Truss’s "mini-budget" in 2022: unlimited government spending, with the market setting the price.

The only difference is that Trump stepped down after 45 days, while Japan’s fiscal expansion lasted for thirty years.

Rate hikes tighten monetary policy, while bond issuance expands it. The central bank hits the brakes, while the finance ministry presses the accelerator. Even more ironically, the Bank of Japan is itself the largest holder of Japanese government bonds—although its monthly bond-buying program is being scaled back, as long as it continues purchasing, every yen spent on government bonds injects one yen into the market. On one hand, raising rates to withdraw liquidity; on the other, buying bonds to inject liquidity—these two actions are effectively canceling each other out.

The market doesn't need to be an economist to understand: every card in the Bank of Japan's hand is countered by another card.

Behind the numbers are real costs.

On July 8, Tokyo Shoko Research announced that in the first half of 2026, 5,346 Japanese companies with liabilities of over 10 million yen went bankrupt, a 7.1% year-over-year increase, marking the fifth consecutive year of growth and the first time since 12 years that the number has exceeded 5,000 in the first half of the year.

45 companies went bankrupt due to the yen's depreciation, a 32.3% year-over-year increase—the highest on record. Wholesale businesses accounted for half—23 out of the 45, up from 14 at this time last year. Additionally, bankruptcies due to labor shortages rose by 37.7%, and those due to rising prices increased by 27.6%.

These figures reveal a fact overshadowed by "record corporate profits": yen depreciation is not universal.

Toyota, Sony, and Hitachi are benefiting from export gains, as overseas profits converted back into yen automatically increase in value. But the vast majority of Japanese companies are not Toyota—they rely on imported raw materials, serve the domestic market, and dare not raise prices. For the past three decades, zero interest rates and a cheap yen have nurtured a vast ecosystem of small and medium-sized enterprises. Now, as interest rates rise, the yen falls, and prices climb, this ecosystem is collapsing.

Labor shortages are the other side of the same coin. Large companies lure away young workers with high wages, while small businesses aren’t lacking orders—they’re lacking workers. Data from Imperial Database during the same period shows that "bankruptcies due to labor shortages" have reached an all-time high.

Three paths, three different costs.

No interest rate hike. The yen continues to depreciate, import costs keep rising, small and medium-sized enterprises continue to fail, and social dissatisfaction continues to accumulate.

Rate hikes. Government bond yields surge, making fiscal policy unsustainable; markets bet that the central bank will eventually be forced by the government to stop—yen continues to depreciate, as markets see only the "exit illusion," not genuine tightening resolve.

Rate hikes accompanied by balance sheet reduction. Japanese bond yields surge, global carry trades reverse, and Japanese investors sell offshore assets and repatriate funds—yen may strengthen in the short term, but the script from August 2024 is already on the table: that time, the Bank of Japan’s unexpected rate hike triggered not a steady yen rebound, but a global stock market crash.

None of the three paths work, because the problem cannot be solved by monetary policy alone. Japan’s 250% government debt, a continuously shrinking labor force, and annually widening fiscal deficits—these are not issues that can be changed by adjusting interest rates by 25 basis points.

On July 6, when Goldman Sachs raised its target to 165, the market wasn’t waiting for the next Bank of Japan meeting—it was pricing in something deeper: whether the Bank of Japan has a chance to win.

The answer is becoming clearer: it was never winnable from the start.

162.62 is not the end, and 165 is also unlikely to be. Unless fiscal discipline miraculously returns or the Fed significantly cuts rates, this "impossible trinity" will only tighten further. The direction of the yen depends not on Tokyo, but on Washington, Riyadh, and the deeper forces within global capital flows.

The Bank of Japan’s only choice is whether to lose this inevitable defeat slowly or catastrophically.