In a rare convergence of monetary will, the United States and Japan have moved together to arrest the yen's long slide — the first such coordinated intervention in nearly three decades. Bank of America, reading the signal, has revised its yen forecast to ¥149 per dollar by year-end 2026, a 6% strengthening from current levels. The forecast rests on the belief that shared commitment between two major economies can dissolve the practical limits of currency defense, but only if Japan's central bank follows through with the rate hikes that give intervention its lasting meaning.