Naoto Kan, the former Japanese prime minister, is set to testify in a public inquiry on the the government's handling of the Fukushima nuclear disaster.
At the hearing, in front of a parliamentary panel, Kan will face questions about what he did immediately following the explosion at the Fukushima Dai-ichi power plant after a massive earthquake and tsunami last year.
In particular, Kan will have to answer why it took his government almost three hours after the plant's reactors automatically shut down to declare an emergency.
Al Jazeera's Mike Firn reports from Tokyo.
