Sony Financial Group Inc. surged in its Tokyo debut on Monday after a rare spinoff-listing by Sony Group Corp.,which is sharpening its focus on its entertainment and image sensor businesses.The shares opened at ¥205 and rose as high as ¥210 before edging lower and closing at ¥173.8 on their first day of trading. That values the Sony Group’s financial unit at ¥1.2 trillion ($8.1 billion) based on the closing price. The reference price for Sony Group’s financial unit was set at ¥150 last week. The insurance a ...