TOKYO, Dec 20 (Reuters) - Japanese shares rose on Tuesday as investors scooped up stocks after the benchmark Nikkei fell to a six-week low in the previous session, although heavyweight technology stocks tracked their U.S.peers lower and limited gains in the benchmark index. By 0213 GMT, the Nikkei share average was up 0.3% at 27,320.85, after losing for three straight sessions. The broader Topix had gained...