Bitcoin traders may need to widen their macro lens, as the cryptocurrency’s relationship with the Japanese yen has tightened to levels not seen before.

Data from TradingView show the 90-day correlation between bitcoin and Pepperstone’s Japanese yen index has risen to 0.86, the highest reading on record. Such a strong correlation indicates the two assets have been moving in the same direction with unusual consistency over the past three months.

In practical terms, around 73% of bitcoin’s price moves during that period can be explained by fluctuations in the yen. This measure, known as the coefficient of determination, is calculated by squaring the correlation coefficient and provides a simple way to gauge how closely two markets track one another.

Pepperstone’s JPY Index, or JPYX, is a currency index CFD that tracks the yen’s performance against a basket of four major currencies — the euro, U.S. dollar, Australian dollar and New Zealand dollar.

The strength of the relationship suggests bitcoin, long promoted as a largely uncorrelated asset, has recently been trading under the influence of Japanese currency dynamics. Over the past 90 days, BTC has tended to rise and fall alongside the yen, weakening its role as a portfolio diversifier and turning what was once framed as “digital gold” into an amplified bet on yen moves.

Still, traders should be cautious about drawing long-term conclusions. Correlations between cryptocurrencies and traditional assets such as currencies and equities are often temporary and can reverse quickly.

Bitcoin peaked in early October before sliding over the following two months, mirroring an extension of the yen’s broader downtrend. Selling pressure in both markets began to ease after mid-December.

The yen has been under pressure since April last year as concerns over Japan’s fiscal sustainability pushed government bond yields higher. With a debt-to-GDP ratio near 240%, Japan ranks among the most indebted economies globally, even though most of its debt is held domestically.

That debt burden leaves the Bank of Japan with limited room to maneuver. Raising interest rates would increase debt-servicing costs and worsen fiscal strains, while keeping policy loose risks a deeper slide in the yen.

Some market participants argue the fiscal stress is already being reflected in currency markets through a sharply weaker yen, and that only a potential U.S. recession may provide Japan with temporary relief.