Complex sentence: In a dramatic display of devotion to the Meiji Emperor, Hirai commits seppuku to divine the year of Tokyo's destruction; which turns out to be 1923, the Year of the Pig.
Split into simpler sentences: In a dramatic display of devotion to the Meiji Emperor, Hirai commits seppuku. However his act divines the year of Tokyo's destruction; 1923, the Year of the Pig.