TOKYO, Dec 21 (Reuters) - Japanese government bond futures rose on Monday as the emergence of a new strain of the coronavirus in Britain boosted demand for safer assets. However, super long-term yields rose slightly after Japan’s government approved a record budget for next fiscal year and said it would sell more 40-year bonds. Benchmark 10-year JGB futures rose 0.06 point to 152.12, with a trading volume of 14,161 lots. The 10-year JGB yield was flat at 0.005%. The 20-year JGB yield was flat at 0.380%. At the long end of the curve, the 30-year JGB yield rose 1 basis point to 0.630%. The 40-year JGB yield also rose 1 basis point to 0.680%. Japan will increase issuance of 40-year JGBs by 100 billion yen ($967.02 million) per auction from April, the finance ministry said on Monday. At the middle of the curve, the five-year yield was flat at minus 0.130%. At the short end, the two-year JGB yield held steady at minus 0.140%.