Stock and bond trading on the Tokyo Stock Exchange was scrapped Tuesday morning as a result of a system glitch.
Problems came to light before the market's opening at 9 a.m. local time (midnight GMT) and caused the start of trading to be delayed until 1:30 p.m. local time.
The glitch is the most serious to hit the exchange since floor trading was scrapped and an all-electronic trading system was installed in 1999. The system, which is supplied by Fujitsu, was upgraded on Oct. 10.
Tuesday's problem appears to have been caused by a software error related to that upgrade, according to local news reports.
Further details were not immediately available.
Despite the problem Tokyo stocks ended overall up on the day. The benchmark Nikkei 225 stock index closed at 13,867.79, up 261.36 points and a four-year high.