Tokyo stocks closed the morning higher Tuesday, supported by gains in leading exporters, despite a computer system failure that suspended derivatives trading for more than an hour and a half. The Nikkei Stock Average reached 8,778.73, up 52.44 points, or 0.60%, ending morning trade in the upper 8,700 level for the first time since July 20, according to the (Nikkei.com) website. Key exporters continued to rise, with Canon Inc. (7751) advancing for the sixth consecutive session. The Tokyo Stock Exchange suspended trading for all derivatives at morning due to a system failure. The broader Topix index of all first-section issues also gained ground. The trading value on the TSE's first section reached 346.2 billion yen, with 664.91 million shares changing hands.