* Nikkei up 0.2 pct, marked fresh 6-month high earlier * Mazda sheds 6 pct on 162 bln yen share offering plans * Banks drop in line with decline in U.S. financials * Euro zone economic contraction worries market By Mari Saito TOKYO, Feb 23 (Reuters) - Japan's Nikkei share average ticked up towards 9,600 in choppy trade, with a softer yen underpinning market sentiment and boosting risk appetite, although caution remained over Europe after data showed weak business activity i