Nikkei futures on the Osaka Stock Exchange fell seven percent from Friday's regular session while Japanese government bond prices jumped more than a half point at opening after Japan suffered its strongest earthquake in its modern history.

The benchmark December euroyen three-month interest rate futures contract opened 0.025 point up at 99.665, before extending gains to 99.690, the highest level for a benchmark contract since early November.

(Reporting by Tokyo Markets Team)