The ratio of Japanese government bonds held by the Bank of Japan fell for the second straight quarter at the end of March but remained high at 53.25 percent of state debt, central bank data showed Thursday. While the ownership rate declined from 53.78 percent in December, the still massive bond holdings, accumulated through years of unorthodox monetary easing steps to create inflation, pose a challenge to the BOJ. It decided to reduce its purchases at its meeting in June. Including short-term bonds, the BOJ’s holdings fell to 47.39 percent at the end of March from 47.90 percent in December. Fo…