The Bank of Japan announced yesterday that it would raise interest rates from 0.5% to 0.75%—the highest level in thirty years. According to conventional logic, this tightening signal should suppress the market, but the crypto space is seeing the opposite: Ethereum price surged past 2900 USDT, with a daily increase of 2.56%, and market sentiment is exceptionally hot.

Here's the interesting part. Recently, investors have been engaging in "yen arbitrage"—borrowing low-cost yen to invest in US stocks or crypto assets—which would be forced to close out positions due to rate hikes. Theoretically, this should create selling pressure, but in practice, it's not that simple.

First, look at the reaction in traditional finance—the Nikkei 225 index dropped 1.3%, which is not surprising. But the crypto market seems unaffected and even rises. Why? The key is that this rate hike was already fully priced in by the market.

Predictions on Polymarket show that the market's expectation of a rate hike is as high as 99%, leaving little suspense. When "bad news" is already fully priced in and everyone is waiting for it to materialize, its actual occurrence becomes a sign of "bad news already priced in"—panic sellers have already exited, leaving behind prepared players, some even lurking at low levels, waiting for this moment.

This market game theory may seem counterintuitive, but it actually hides deep logic. The difference between expectations and reality often determines the direction of prices.