As a general rule, the circuit breaker trigger levels are not to be expanded from the fourth CB trigger. In view of the recent market climate, however, the Exchange applies an exceptional rule for the process following a CB trigger for all listed commodities during the sessions for clearing period dated September 26, 2011, as follows:
(1) For the first, second, third, forth and fifth CB triggers, the trading session will be halted for 5 minutes from the time of the trigger. Trading will then resume with an expanded CB.
(2) From the sixth CB trigger, trading will resume after a 5-minute halt, but the CB trigger level will not be expanded (for the gold example above, the CB trigger level will stay at JPY 500). However, when deemed necessary by the Exchange, the halt period and trigger level expansion may be modified.
For the current CB trigger levels, please refer here1 and 2.