Bank of Japan

The Bank of Japan (BoJ) is the central bank of Japan and one of the world’s most powerful monetary authorities, managing policy for the third-largest economy. For three decades, the BoJ has been engaged in an economic experiment most central banks dread: fighting persistent deflation and very low growth in a developed economy.

The lost decade(s) and persistent deflation

Japan’s experience in the 1990s and beyond was unlike anything most central banks had to manage. After the collapse of the asset-price bubble in 1990, Japanese inflation did not just slow — it became zero or negative. Deflation is dangerous because it changes the incentives of consumers and businesses: if you expect prices to fall tomorrow, why spend money today? You wait. This creates a vicious cycle of weak demand, falling prices, and weak growth. The BoJ, despite early attempts at stimulus, could not break the cycle for years.

The zero interest-rate policy era

By 1999, the BoJ cut its policy rate to zero and kept it there for years. This was shocking to most economists at the time — a central bank simply did not operate with zero rates. But Japan had no choice. With inflation stuck at zero or negative, cutting rates to zero still left real rates (adjusted for deflation) very high. The BoJ’s rate was ineffective. By the early 2000s, the BoJ moved to quantitative easing, buying government bonds and other assets in hopes of expanding the money supply and breaking the deflation trap. The BoJ was the first major central bank to use QE, before the Federal Reserve or ECB tried it.

Abenomics and the assault on deflation

In 2012, Japan elected Prime Minister Shinzo Abe on a platform of aggressive stimulus. As part of “Abenomics,” the Bank of Japan’s new governor, Haruhiko Kuroda, promised to end deflation through “massive” monetary expansion. The BoJ committed to a 2% inflation target, doubled its monthly asset purchases, and extended the maturity of bonds it bought to push longer-term interest rates down. The program was more aggressive than the Federal Reserve or ECB had dared. Abenomics did succeed in moving inflation toward 2%, though partly by accident — a weaker yen boosted import costs — and growth picked up for a time.

Negative rates and yield-curve control

In January 2016, the BoJ did something virtually no major central bank had done: it adopted explicitly negative interest rates, charging banks a small fee to hold excess reserves. The goal was to make holding cash painful and encourage lending. Later, the BoJ refined the approach with “yield-curve control” — directly managing the level of interest rates at different maturities along the government bond curve, not just the overnight rate. This was an even more hands-on approach to monetary control than traditional quantitative easing.

The pandemic and yield-curve control refined

When COVID-19 hit, the BoJ expanded its asset purchases and held its yield-curve-control band steady even as inflation began to rise globally. The BoJ remained highly accommodative longer than many of its peers, reluctant to tighten after decades of fighting deflation. Only in 2024 did the BoJ finally raise its policy rate above zero, a historic moment after 16+ years of zero or negative rates. The BoJ’s cautious approach reflected deep institutional memory of the pain of tight policy in a deflationary environment.

What the BoJ’s experience teaches other central banks

Japan’s three decades of deflation and low growth offer a cautionary tale: monetary policy alone cannot overcome fundamental economic problems like weak productivity or an aging population. Once an economy enters a deflationary trap, escaping it is extraordinarily difficult, even with a determined central bank. The BoJ also showed that extreme monetary measures — zero rates, quantitative easing, negative rates, yield-curve control — can keep an economy from collapsing but cannot always restore robust growth. This is why most economists now argue that fiscal policy (government spending) must accompany monetary stimulus in severe recessions.