Iwaki will conduct members of the NHK Orchestra, with other musicians, in a concert that begins at 3:30 p.m., and will likely last over six hours. There will be five intermissions.
Last year, Iwaki and two other conductors took turns conducting two orchestras in a lengthy New Year's Eve performance. This year, the 72-year-old conductor plans to lead the marathon by himself.
"Beethoven is special," Iwaki said. "I'd be happy even if I died during the performance.