Thirteen Japanese cult members may be sent to the gallows any day now for a deadly 1995 gas attack on the Tokyo subway system and other crimes.

However when is uncertain, such is the secrecy that surrounds Japan’s death penalty system.

Tuesday marks 23 years since members of the Aum Shinrikyo cult punctured plastic bags to release sarin nerve gas inside subway cars, poisoning thousands and killing 13.

Cult leader Shoko Asahara and a dozen followers have been sentenced to death for that and other crimes that killed 27 in all.

The relocation of seven of them to five detention centres outside of Tokyo last week has sparked speculation that executions could be imminent. In Japan, accomplices in a crime are customarily hanged on the same day.

Ten of those on death row were convicted for the subway attack, a number beyond the Tokyo detention centre’s daily capacity.

As with all executions in Japan, when and where they will be killed isn’t being released, even to family members and lawyers. The executions won’t be announced until they have already happened.

Shizue Takahashi, the wife of a subway stationmaster who died in the gas attack, asked the Justice Ministry for a chance to meet the convicts and witness their executions. “I want to follow through to the very end,” Takahashi said at a recent news conference.

Her wish is unlikely to be granted.

Even prisoners sent to the gallows are not notified until guards come to their cells in the morning. After a chat with a chaplain, a last bite or smoke, the prisoner is taken to the gallows.

-AAP