The yield on 10-year Japanese government bonds broke through the upper band of the Bank of Japan’s yield curve target today (June 13), prompting another bond purchase operation by the central bank.

Benchmark bond yields briefly touched 0.27%, before falling back to 0.255%, still a fraction above the BoJ’s 0.25% upper limit. The central bank is committing to keeping 10-year yields around zero, but allows 25 basis points of movement in either direction.

The BoJ said it would buy bonds worth 500