TOKYO, Sept 13 (Reuters) - Japanese stocks staged a late comeback to take the Topix to a three-decade peak on Monday, buoyed by optimism around a change in the country’s prime minister and easing COVID-19 infections. The Topix crossed into positive territory in the final 20 minutes of trading and ended the day up 0.29% at 2,097.71, the highest close since 1990. That extended a scorching three-week, 11% rally. The Nikkei share average rose 0.22% to 30,447.37, marking an almost seven-month closing high. The gains came despite weakness in global equities overall. An index of Asia-Pacific shares excluding Japan slid 1%, in line with Wall Street’s declines from Friday.“There is some caution about how high Japanese stock prices are after last week’s sudden gains, but retail investors in particular have a strong desire to buy,” said a market participant at a domestic securities firm. “Foreign investors are also buying.” Iron and steel was the best-performing Topix sector, followed by oil and coal producers adding 1.56% and 1.48%, respectively, as commodity prices surged. Banking was the third-best performer, up 1.07%, as Shinsei Bank rallied for a second day, rising 12.99% after an unsolicited bid by SBI Holdings on Thursday. Chipmakers also gained, with Tokyo Electron and Advantest supporting the Nikkei the most in terms of index points, rising 1.5% and 1.98%, respectively.At the other end, transport equipment was the worst-performing sector on the Topix, dropping 1.39% after Toyota last week announced extra lost production of 400,000 vehicles over this month and the next. Japan’s biggest automaker slumped 1.65%, while Honda fell 1.28% and Nissan declined 1.14%. On the Nikkei, consumer cyclical stocks fell the most, down 0.93%. Uniqlo store operator Fast Retailing was the third-biggest drag on the index, falling 0.28%. SoftBank Group was the biggest weight, losing 1.43%. (Reporting by Tokyo markets team; Editing by Devika Syamnath)