TOKYO, Oct 5 (Reuters) - Japanese shares tumbled to one-month lows on Tuesday as spikes in oil prices stoked further worries about inflation and monetary tightening globally. Nikkei share average fell 2.97% to 27,602.33, piercing below 27,865, its 76.4% retracement of its rally from late August to September, with next support at 26,954, its Aug. 20 low. The broader Topix shed 1.79% at 1,938.66, on course to log its seventh consecutive losing session and hitting its lowest level since Aug. 27. “There’s a sense that the assumption investors have had, that inflation will be temporary and earnings will continue to recover, may be crumbling,” said Masayuki Doshida, senior market analyst at Rakuten Securities. Some market players said new Japanese Prime Minister Fumio Kishida’s proposal to raise tax on capital gains also undermined sentiment. Growth shares that have benefited from low interest rates underperformed sharply, with Topix Growth Index falling 2.0%, compared with 0.7% drop in Topix Value. Fast Retailing dived 6.9% after the operator of Uniqlo casual clothing chain reported a 19.1% fall in its existing store sales in September. Internet firm Z Holdings lost 6.8% while electronic parts maker Murata Manufacturing shed 4.1%. SoftBank Group lost 5.1% on concerns about falling values of its investment in tech firms, in particular Alibaba , which has fallen over 50% from a record peak hit almost a year ago. Semiconductor-related shares also suffered with MSCI’s Japan semi-conductor index lost 4.7%. Bucking the trend were oil companies, which benefited from rising crude oil prices. Oil exploration company Inpex rose 5.5% while Idemitsu Kosan was up 2.3%. Life insurers also benefited from higher U.S. bond yields, with T&D Holdings up 1.1% and Dai-ichi Life Holdings gaining 0.9%. Reporting by Hideyuki Sano; Editing by Krishna Chandra Eluri Our Standards: The Thomson Reuters Trust Principles.